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  Subjects -> CHEMISTRY (Total: 843 journals)
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    - PHYSICAL CHEMISTRY (66 journals)

INORGANIC CHEMISTRY (41 journals)

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Acta Polymerica     Hybrid Journal   (Followers: 7)
Additives for Polymers     Full-text available via subscription   (Followers: 20)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Polymer Technology     Hybrid Journal   (Followers: 12)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 3)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 8)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 1)
Current Methods in Inorganic Chemistry     Full-text available via subscription   (Followers: 1)
European Journal of Inorganic Chemistry     Hybrid Journal   (Followers: 7)
European Polymer Journal     Hybrid Journal   (Followers: 40)
Heterocyclic Communications     Hybrid Journal  
High Performance Polymers     Hybrid Journal  
Indian Journal of Chemistry - Section A     Open Access   (Followers: 7)
Inorganic Chemistry     Full-text available via subscription   (Followers: 20)
Inorganic Chemistry Communications     Hybrid Journal   (Followers: 9)
Inorganic Chemistry Frontiers     Full-text available via subscription   (Followers: 1)
Inorganic Materials     Hybrid Journal   (Followers: 3)
Inorganic Materials: Applied Research     Hybrid Journal   (Followers: 1)
Inorganica Chimica Acta     Hybrid Journal   (Followers: 5)
Inorganics     Open Access  
International Journal of Bio-Inorganic Hybrid Nanomaterials     Open Access  
International Journal of Inorganic Chemistry     Open Access   (Followers: 1)
JBIC Journal of Biological Inorganic Chemistry     Hybrid Journal   (Followers: 4)
Journal of Inorganic and Organometallic Polymers and Materials     Partially Free   (Followers: 6)
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 3)
Journal of Polymer Engineering     Hybrid Journal   (Followers: 8)
Journal of Polymers and the Environment     Hybrid Journal   (Followers: 1)
Journal of Separation Science     Hybrid Journal   (Followers: 11)
Metallodrugs     Open Access   (Followers: 1)
Open Journal of Inorganic Chemistry     Open Access   (Followers: 2)
Plasmas and Polymers     Hybrid Journal  
Polymer Bulletin     Hybrid Journal   (Followers: 7)
Polymer Composites     Hybrid Journal   (Followers: 13)
Polyoxometalate Chemistry     Open Access  
Reviews in Inorganic Chemistry     Hybrid Journal  
Russian Journal of Inorganic Chemistry     Hybrid Journal  
Studies in Inorganic Chemistry     Full-text available via subscription  
Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry     Hybrid Journal   (Followers: 2)
Topics in Inorganic and General Chemistry     Full-text available via subscription  
Zeitschrift für anorganische und allgemeine Chemie     Hybrid Journal   (Followers: 2)
Zeitschrift für Kristallographie - New Crystal Structures     Open Access  
Journal Cover Journal of Inorganic Biochemistry
  [SJR: 0.96]   [H-I: 87]   [3 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0162-0134
   Published by Elsevier Homepage  [2969 journals]
  • In vitro and in vivo antitumor activity of a novel carbonyl ruthenium
           compound, the
           ct-[RuCl(CO)(dppb)(bipy)]PF­6[dppb=1,4-bis(disphenylphosphine)butane and
           bipy=2,2'-bipyridine]
    • Abstract: Publication date: Available online 25 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Andréa P. Carnizello, Marília I.F. Barbosa, Monize Martins, Natália H. Ferreira, Pollyanna F. Oliveira, Geórgia M. Magalhães, Alzir A. Batista, Denise C. Tavares
      This study performed in vitro and in vivo biological assays of the ruthenium (II) compound ct-[RuCl(CO)(dppb)(bipy)]PF6 (where, dppb =1.4-bis(diphenylphosphine)butane and bipy =2.2′-bipyridine). The cytotoxic activity of this compound was evaluated against different tumor cell lines (HeLa, human cervical adenocarcinoma; MCF7, human breast adenocarcinoma; MO59J, human glioblastoma; HepG2, hepatocellular carcinoma and B16F10, murine melanoma) and healthy cell line (V79, Chinese hamster lung fibroblasts), by XTT (sodium 2,3′-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)-carbonyl]-3,4-tetrazolium]-bis(4-methoxy-6-nitro)benzene-sulfonic acid hydrate) method. A syngeneic murine melanoma tumor model (B16F10) was used to evaluate its antitumor activity. Additionally, experiments were performed to assess the interactions with ctDNA (calf thymus DNA) and BSA (bovine serum albumin). The results showed that ct-[RuCl(CO)(dppb)(bipy)]PF6 was cytotoxic against all tumor cell lines tested. Furthermore, the compound was more effective against tumor cells compared to the normal cell line, indicating selectivity, especially in B16F10 cells. Significant tumor growth reduction was observed in animals treated with the compound compared to the untreated control. Histopathological analysis of tumor tissue revealed a significant reduction of mitosis in animals treated with the compound compared to the untreated control. In the ctDNA and BSA interaction experiments, the compound in study showed weak interactions with ctDNA and hydrophobic interactions with BSA. The ruthenium compound investigated showed promising results in in vitro and in vivo biological assays.
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      PubDate: 2016-08-26T11:07:05Z
       
  • In Situ Synthesis of High Swell Ratio Polyacrylic Acid/Silver
           Nanocomposite Hydrogels and Their Antimicrobial Properties
    • Abstract: Publication date: Available online 24 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Yi-Syuan Wei, Ko-Shao Chen, Lii-Tzu Wu
      Silver nanocomposites embedded within a polymer matrix have attracted attention in recent years. Ionic polymer hydrogels comprise networks of chemically or physically cross-linked polymers that swell considerably in an appropriate solvent. In this study, we used a solution of the carboxylic monomer acrylic acid and silver nitrate to prepare nanocomposite hydrogels through ultraviolet (UV)-light irradiation. Silver-impregnated biomaterial composed of acrylic acid contains only a monomer and no cross-linker. The formation of hydrogels and reduction of silver nanoparticles were affected by the preparation parameters, that is, the monomer concentration and silver nitrate concentration. The morphology, structure, and size of the silver nanocomposite hydrogels were evaluated through field emission scanning electron microscopy and UV–visible absorption. The antimicrobial activity of the samples was tested against fourstandard strains Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli; and five clinical bacterial isolates Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumonia. The silver nanocomposite hydrogels exhibited an interconnected porous structure and could absorb 400 to 550g of deionized water per gram of dried hydrogel. Moreover, these hydrogels produced a strong antibacterial effect, which can be useful in developing new superabsorbent antimicrobial pharmaceutical products.
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      PubDate: 2016-08-26T11:07:05Z
       
  • The effects of the glycation of transferrin on chromium binding and the
           transport and distribution of chromium In Vivo
    • Abstract: Publication date: Available online 25 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Ge Deng, Samantha L. Dyroff, Molly Lockart, Michael K. Bowman, John B. Vincent
      Chromium (III) has been shown to act as a pharmacological agent improving insulin sensitivity in rodent models of obesity, insulin resistance, and diabetes. To act in beneficial fashion, chromium must reach insulin-sensitive tissues. Chromium is transported from the bloodstream to the tissues by the iron-transport protein transferrin. When blood concentrations of glucose are high (as in a diabetic subject), transferrin can be glycated, modifying its ability to bind and transport iron. However, the effects of glycation of transferrin on its ability to bind and transport Cr have not been examined previously. Storage of transferrin at 37°C in the presence and absence of glucose has significant effects on the binding of Cr. Transferrin stored in the absence of glucose only binds one equivalent of Cr tightly, compared to the normal binding of two equivalents of Cr by transferrin. Glycated transferrin (stored in the presence of glucose) binds two equivalents of Cr but the changes in its extinction coefficient at 245nm that accompany binding suggest that the Cr-bound transferrin possesses a conformation that deviates appreciably from untreated transferrin. These changes have dramatic effects, greatly reducing the ability of transferrin to transport Cr in vivo in rats. The results suggest that glycation of transferrin in subjects with high blood glucose concentrations should reduce the ability of Cr from pharmacological agents to enter tissues.
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      PubDate: 2016-08-26T11:07:05Z
       
  • The Heme-Based Oxygen Sensor Rhizobium etli FixL: Influence of Auxiliary
           Ligands on Heme Redox Potential and Implications on the Enzyme Activity
    • Abstract: Publication date: Available online 26 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Nathalie Honorio-Felício, Marta S.P. Carepo, Tércio de F. Paulo, Luiz Gonzaga de França Lopes, Eduardo H.S. Sousa, Izaura C.N. Diógenes, Paul V. Bernhardt
      Conformational changes associated to sensing mechanisms of heme-based protein sensors are a key molecular event that seems to modulate not only the protein activity but also the potential of the FeIII/II redox couple of the heme domain. In this work, midpoint potentials (E m) assigned to the FeIII/II redox couple of the heme domain of FixL from Rhizobium etli (ReFixL) in the unliganded and liganded states were determined by spectroelectrochemistry in the presence of inorganic mediators. In comparison to the unliganded ReFixL protein (+19mV), the binding to ligands that switch off the kinase activity induces a negative shift, i. e. E m =−51, −57 and −156mV for O2, imidazole and CN−, respectively. Upon binding to CO, which does not affect the kinase active, E m was observed at +21mV. The potential values observed for FeIII/II of the heme domain of ReFixL upon binding to CO and O2 do not follow the expected trend based on thermodynamics, assuming that positive potential shift would be expected for ligands that bind to and therefore stabilize the FeII state. Our results suggest that the conformational changes that switch off kinase activity upon O2 binding have knock-on effects to the local environment of the heme, such as solvent rearrangement, destabilize the FeII state and counterbalances the FeII-stabilizing influence of the O2 ligand.
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      PubDate: 2016-08-26T11:07:05Z
       
  • Triphenylphosphane Pt(II) complexes containing biologically active natural
           polyphenols: Synthesis, crystal structure, molecular modeling and
           cytotoxic studies
    • Abstract: Publication date: Available online 9 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Maria Michela Dell’Anna, Valentina Censi, Benedetta Carrozzini, Rocco Caliandro, Nunzio Denora, Massimo Franco, Daniele Veclani, Andrea Melchior, Marilena Tolazzi, Piero Mastrorilli
      Platinum complexes bearing phosphane ligands in cis configuration with deprotonated flavonoids (3-hydroxyflavone, quercetin) and deprotonated ethyl gallate were synthesized starting from cis-[PtCl2(PPh3)2]. In all cases, O,O’ chelate structures were obtained. While quercetin and ethyl gallate complexes are quite stable in solution, the 3-hydroxyflavonate complex undergoes a slow aerobic photodegradation in solution with formation of salicylic and benzoic acids. The XRD structures of quercetin and ethyl gallate complexes are reported. Cell cycle studies (in the dark) of the complexes in two human cell lines revealed that the cytotoxic activity of the complex bearing 3-hydroxyflavonate is higher than those exhibited by 3-hydroxyflavone or by cis-[PtCl2(PPh3)2] alone. DFT studies on the hydrolysis pathway for the 3-hydroxyflavone and ethyl gallate complexes explained the different cytotoxic activity observed for the two compounds on the basis of the different intermediates formed during hydrolysis (relatively inert hydroxy Pt complexes for ethyl gallate and monoaqua complexes for 3-hydroxyflavone).
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      PubDate: 2016-08-13T10:11:10Z
       
  • The synergistic antibacterial activity and mechanism of multicomponent
           metal ions-containing aqueous solutions against Staphylococcus aureus
    • Abstract: Publication date: Available online 5 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Xiaolan Wang, Shaoxiang Liu, Mei Li, Peng Yu, Xiao Chu, Lihua Li, Guoxin Tan, Yingjun Wang, Xiaofeng Chen, Yu Zhang, Chengyun Ning
      Silver (Ag+), zinc (Zn2+) and copper (Cu2+) ions, are well known for their broad-spectrum antibacterial activities while generating low resistance. However, whether or multiple metal ions in aqueous solutions acted synergistically or antagonistically antimicrobial properties, remained unknown. Therefore, it was of great significance to investigate the antibacterial properties of multicomponent metal ions-containing aqueous solutions. In this study, the antibacterial activities of multicomponent metal ions-containing aqueous solutions were investigated for the first time. We found that the antibacterial activities of multicomponent metal ions-containing aqueous solutions were higher than those of single metal ion-containing aqueous solution. Furthermore, the synergistic antibacterial mechanism of these multicomponent metal ions-containing aqueous solutions was first investigated. The generation of reactive oxygen species (ROS) through electron transfer in the enzymes and Fenton reactions formed the main synergistic antibacterial mechanism of the multicomponent metal ions-containing aqueous solutions. Therefore, the encouraging results demonstrate the great potential applications of multicomponent metal ions for the design of new biomaterials or prosthesis containing Ag-Cu-Zn alloy which can release Ag+, Zn2+ and Cu2+ and minimize the risk of hospital acquired infection.
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      PubDate: 2016-08-08T09:43:52Z
       
  • Near-infrared luminescence and RNA cleavage ability of lanthanide Schiff
           base complexes derived from
           N,N′-bis(3-methoxysalicylidene)ethylene-1,2-diamine ligands
    • Abstract: Publication date: Available online 5 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Anna M. Kaczmarek, Piotr W. Alvarez Porebski, Tineke Mortier, Frederic Lynen, Rik Van Deun, Kristof Van Hecke
      A complete series of lanthanide Schiff base salen-type complexes were prepared with trivalent lanthanide ions (Ln3+) and the N,N′-bis-(3-methoxysalicylidene)ethylene-1,2-diamine ligand (Ln3+ =La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+, Lu3+). Three unique crystal structures of La3+ and Pr3+ N,N′-bis-(3-methoxysalicylidene)ethylene-1,2-diamine complexes, with the La3+ complex prepared in two different synthetic approaches, are reported, namely a dimeric [La(H2L)(NO3)3]2 (H2L= N,N′-bis-(3-methoxysalicylidene)ethylene-1,2-diamine) complex, an asymmetric two-centered [La2(H2L)2(NO3)6] complex and a discrete mononuclear [Pr(H2L)(NO3)2(H2O)2] complex. For Nd3+ and Sm3+, an isotypic mononuclear [Nd(H2L)(NO3)3] and 1D polymeric [Sm(H2L)(NO3)3(MeOH)]n structure was obtained, respectively. The whole series of complexes was tested for their ability to cleave the 20-mer RNA oligonucleotide 5′-AGC-GAU-AAG-AUU-CAU-AUA-UC-3′. Additionally three complexes (Ln3+ =Nd3+, Sm3+, Ho3+) were tested for the cleavage of the 12-mer RNA oligonucleotide 5′-GCA-CCC-UGU-CAG-3′. A detailed luminescence study was additionally carried out and revealed that the Eu3+ complex emitted bright red light upon excitation at both 285.8nm and 394.4nm. The Nd3+, Er3+, and Yb3+ complexes showed strong emission in the near-infrared region after excitation at 380nm.
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      PubDate: 2016-08-08T09:43:52Z
       
  • Enzymatic oxidation of ansa-ferrocifen leads to strong and selective
           thioredoxin reductase inhibition in vitro
    • Abstract: Publication date: Available online 5 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Valeria Scalcon, Anna Citta, Alessandra Folda, Alberto Bindoli, Michèle Salmain, Ilaria Ciofini, Sébastien Blanchard, José de Jesus Cazares-Marinero, Yong Wang, Pascal Pigeon, Gérard Jaouen, Anne Vessières, Maria-Pia Rigobello
      This paper reports the inhibitory effecton the cytosolic thioredoxin reductase (TrxR1) in vitro by the ansa-ferrocifen derivative (ansa-FcdiOH, 1). We found that 1 decreased only slightly enzyme activity (IC50 =8μM), while 1*, the species generated by enzymatic oxidation by HRP (horseradish peroxidase)/H2O2 mixture, strongly inhibited TrxR1 (IC50 =0.15μM). At the same concentrations, neither 1 nor 1* had effect on glutathione reductase (GR). The most potent TrxR1 inhibitor did not appear to be the corresponding quinone methide as it was the case for ferrocifens of the acyclic series, or the stabilized carbocation as in the osmocifen series, but rather the quinone methide radical. This hypothesis was confirmed by ab-initio calculations of the species generated by oxidation of 1 and by EPR spectroscopy. BIAM (biotin-conjugated iodoacetamide) assay showed that 1* targeted both cysteine and selenocysteine of the C-terminal redox center of TrxR1.
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      PubDate: 2016-08-08T09:43:52Z
       
  • Visible light-induced formation of corrole-manganese(V)-oxo complexes:
           Observation of multiple oxidation pathways
    • Abstract: Publication date: Available online 5 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Wai Kwong Ka, Fung Lee Ngo, Davis Ranburger, Jonathan Malone, Rui Zhang
      Two manganese(V)-oxo corroles [MnV(Cor)O] that differ in their electronic environments were produced by visible light irradiation of highly photo-labile corrole-manganese(IV) bromates. The corrole ligands under study include 5,10,15-tris(pentafluorophenyl)corrole (TPFC), and 5,10,15-triphenylcorrole (TPC). The kinetics of oxygen transfer atom (OAT) reactions with various organic reductants by these photo-generated MnV(Cor)O were also studied in CH3CN and CH2Cl2 solutions. MnV(Cor)O exhibits remarkable solvent and ligand effect on its reactivity and spectral behavior. In the more electron-deficient TPFC system and in the polar solvent CH3CN, MnV(Cor)O returned MnIII corrole in the end of oxidation reactions. However, in the less polar solvent CH2Cl2 or in the less electron-deficient TPC system, MnIV product was formed instead. Furthermore, with the same substrates and in the same solvent, the order of reactivity of MnV(Cor)O was TPC>TPFC, which is inverted from that expected based on the electron-demand of corrole ligands. Our spectral and kinetic results in this study provide compelling evidence in favor of multiple oxidation pathways, where MnV(Cor)O may serve as direct two-electron oxidant or undergo a disproportionation reaction to form a manganese(VI)-oxo corrole as the true oxidant. The choice of pathways is strongly dependent on the nature of the solvent and the corrole ligand.
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      PubDate: 2016-08-08T09:43:52Z
       
  • Physico-chemical properties of MnII complexes formed with cis- and
           trans-DO2A†: Thermodynamic, electrochemical and kinetic studies
    • Abstract: Publication date: Available online 2 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Zoltán Garda, Attila Forgács, Quyen N. Do, Ferenc K. Kálmán, Sarolta Timári, Zsolt Baranyai, Lorenzo Tei, Imre Tóth, Zoltán Kovács, Gyula Tircsó
      Manganese (MnII) is a promising alternative to gadolinium (GdIII) as a magnetic resonance imaging (MRI) agent. Unlike gadolinium, this biogenic metal might be better tolerated by the body, reducing the risk of toxicity associated with dissociation of the complex. Herein we report detailed equilibrium and kinetic studies performed with MnII complexes of 1,4,7,10-tetraazacyclododecane-1,4-diacetic acid (1,4-DO2A or cis-DO2A) and 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (1,7-DO2A or trans-DO2A). The protonation constants of the ligands as well as stability constants of their MnII complexes have been determined by pH-potentiometry. The stability constants of [Mn(cis-DO2A)] are slightly higher than that of [Mn(trans-DO2A)] (log K MnL =15.68 and 15.22, respectively). Cyclic voltammetric (CV) experiments performed on [Mn(cis-DO2A)] and [Mn(trans-DO2A)] revealed quasireversible systems with a half-wave potential of +636 and +705mV versus Ag/AgCl, respectively. These values indicate that the MnII ion in these complexes is more stabilized against the oxidation than in [Mn(EDTA)]2−. The kinetic inertness of the complexes has been studied in transmetallation reactions with CuII or ZnII ions. Kinetic measurements indicate that both MnII complexes primarily undergo acid catalyzed dissociation and positions of the acetate pendant arms do not influence kinetic inertness. The kinetic inertness of these complexes is comparable to that of [Mn(NOTA)]− and significantly (about twenty times) lower than that of [Mn(DOTA)]2−. In conclusion, [Mn(cis-DO2A)] displays some very interesting features (thermodynamic and redox stability as well as kinetic inertness) which makes this complex a promising platform for the development of more efficient MnII complexes as alternatives to Gd-based MRI agents.
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      PubDate: 2016-08-04T09:26:11Z
       
  • Design, syntheses, characterization, and cytotoxicity studies of novel
           heterobinuclear oxindolimine copper(II)-platinum(II) complexes
    • Abstract: Publication date: Available online 3 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Esther Escribano Aranda, Tiago Araújo Matias, Koiti Araki, Adriana Pires Vieira, Elaine Andrade de Mattos, Pio Colepicolo, Carolina Portela Luz, Fábio Luiz Navarro Marques, Ana Maria da Costa Ferreira
      Herein, the design and syntheses of two new mononuclear oxindolimine-copper(II) (1 and 2) and corresponding heterobinuclear oxindolimine Cu(II)Pt(II) complexes (3 and 4), are described. All the isolated complexes were characterized by spectroscopic techniques (UV/Vis, IR, EPR), in addition to elemental analysis and mass spectrometry. Cyclic voltammetry (CV) measurements showed that in all cases, one-electron quasi-reversible waves were observed, and ascribed to the formation of corresponding copper(I) complexes. Additionally, waves related to oxindolimine ligand reduction was verified, and confirmed using analogous oxindolimine-Zn(II) complexes. The Pt(IV/II) reduction, and corresponding oxidation, for complexes 3 and 4 occurred at very close values to those observed for cisplatin. By complementary fluorescence studies, it was shown that glutathione (GSH) cannot reduce any of these complexes, under the experimental conditions (room temperature, phosphate buffer 50mM, pH7.4), using an excess of 20-fold [GSH]. All these complexes showed characteristic EPR spectral profile, with parameters values gǁ >g⊥ suggesting an axially distorted environment around the copper(II) center. Interactions with calf thymus-DNA, monitored by circular dichroism (CD), indicated different effects modulated by the ligands. Finally, the cytotoxicity of each complex was tested toward different tumor cells, in comparison to cisplatin, and low values of IC50 in the range 0.6 to 4.0μM were obtained, after 24 or 48h incubation at 37°C. The obtained results indicate that such complexes can be promising alternative antitumor agents.
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      PubDate: 2016-08-04T09:26:11Z
       
  • Kinetics and thermodynamics of zinc(II) and arsenic(III) binding to XPA
           and PARP-1 zinc finger peptides
    • Abstract: Publication date: Available online 2 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Juliana Huestis, Xixi Zhou, Li Chen, Changjian Feng, Laurie G. Hudson, Ke Jian Liu
      Inhibition of DNA repair is an established mechanism of arsenic co-carcinogenesis, and may be perpetuated by the binding of As(III) to key zinc finger (zf) DNA repair proteins. Validated molecular targets of As(III) include the first zinc finger domain of Poly (ADP-Ribose) Polymerase 1 (PARP-1), and the zinc finger domain of Xeroderma Pigmentosum Complementation Group A (XPA). In order to gain an understanding of the thermodynamic and kinetic parameters of the interaction of As(III) with these two zinc finger motifs, a fluorescence based approach was used to investigate Zn(II) and As(III) binding to synthetic model peptides corresponding to the zf motif of XPA and first zf motif of PARP-1, referred to in this paper as XPAzf and PARP-1zf-1, respectively. While XPAzf and PARP-1zf-1 display similar relative affinities for As(III), PARP-1zf-1 shows a potential kinetic advantage over XPAzf for As(III) binding, with a rate constant for the fast phase of formation of As(III)-PARP-1zf-1 approximately 4-fold higher than for As(III)-XPAzf. However, the binding of Zn(II) with either peptide proceeds at a faster rate than As(III). Notably, XPAzf demonstrates comparable affinities for binding both metals, while PARP-1zf-1 shows a slightly higher affinity for Zn(II), suggesting that the relative concentrations of Zn(II) and As(III) in a system may significantly influence which species predominates in zinc finger occupancy. These results provide insight into the mechanisms underlying interactions between zinc finger structures and As(III), and highlight the potential utility of zinc supplementation in mitigating adverse effects of As(III) on zinc finger functions in vivo.
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      PubDate: 2016-08-04T09:26:11Z
       
  • In vitro antibacterial and time kill evaluation of mononuclear
           phosphanegold(I) dithiocarbamates
    • Abstract: Publication date: Available online 3 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Bao-Jing Chen, Nazzatush Shimar Jamaludin, Chai-Hoon Khoo, Tian-Hong See, Jiun-Horng Sim, Yoke-Kqueen Cheah, Siti Nadiah Abdul Halim, Hoi-Ling Seng, Edward R.T. Tiekink
      Four compounds, R3PAu[S2CN(CH2CH2OH)2], R=Ph (1) and Cy (2), and Et3PAuS2CNRꞌ2, Rꞌ=Rꞌ=Et (3) and Rꞌ2 =(CH2)4 (4), have been evaluated for antibacterial activity against a panel of 24 Gram positive (8) and Gram negative (16) bacteria. Based on minimum inhibitory concentration (MIC) scores, compounds 1 and 2 were shown to be specifically potent against Gram positive bacteria whereas compounds 3 and, to a lesser extent, 4 exhibited broad range activity. All four compounds were active against methicillin resistant Staphylococcus aureus (MRSA). Time kill assays revealed the compounds to exhibit both time- and concentration-dependent pharmacokinetics against susceptible bacteria. Each compound was bactericidal against one or more bacteria with 3 being especially potent after 8h exposure; compounds 1 and 3 were bactericidal against MRSA. Compound 3 was the most effective bactericide across the series especially toward B. subtilis, S. saprophyticus, A. hydrophila, P. vulgaris, and V. parahaemolyticus. This study demonstrates the potential of this class of compounds as antibacterial agents, either broad range or against specific bacteria.
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      PubDate: 2016-08-04T09:26:11Z
       
  • Design and cellular studies of a carbon nanotube-based delivery system for
           a hybrid platinum-acridine anticancer agent
    • Abstract: Publication date: Available online 27 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Cale D. Fahrenholtz, Song Ding, Brian W. Bernish, Mariah L. Wright, Ye Zheng, Mu Yang, Xiyuan Yao, George L. Donati, Michael D. Gross, Ulrich Bierbach, Ravi Singh
      A three-component drug-delivery system has been developed consisting of multi-walled carbon nanotubes (MWCNTs) coated with a non-classical platinum chemotherapeutic agent ([PtCl(NH3)2(L)]Cl (P3A1; L= N-(2-(acridin-9-ylamino)ethyl)-N-methylproprionimidamide) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-5000] (DSPE-mPEG). The optimized P3A1-MWCNTs are colloidally stable in physiological solution and deliver more P3A1 into breast cancer cells than treatment with the free drug. Furthermore, P3A1-MWCNTs are cytotoxic to several cell models of breast cancer and induce S-phase cell cycle arrest and non-apoptotic cell death in breast cancer cells. By contrast, free P3A1 induces apoptosis and allows progression to G2/M phase. Photothermal activation of P3A1-MWCNTs to generate mild hyperthermia potentiates their cytotoxicity. These findings suggest that delivery of P3A1 to cancer cells using MWCNTs as a drug carrier may be beneficial for combination cancer chemotherapy and photothermal therapy.
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      PubDate: 2016-07-30T08:53:02Z
       
  • The adipogenic potential of Cr(III). A molecular approach exemplifying
           metal-induced enhancement of insulin mimesis in diabetes mellitus II
    • Abstract: Publication date: Available online 27 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): O. Tsave, M.P. Yavropoulou, M. Kafantari, C. Gabriel, J.G. Yovos, A. Salifoglou
      Insulin resistance is identified through numerous pathophysiological conditions, such as Diabetes mellitus II, obesity, hypertension and other metabolic syndromes. Enhancement of insulin action and\or its complete replacement by insulin-enhancing or insulin-mimetic agents seems to improve treatment of metabolic diseases. Over the last decades, intensive research has targeted the investigation of such agents, with chromium emerging as an important inorganic cofactor involved in the requisite metabolic chemistry. Chromium in its trivalent state has been shown to play a central role in carbohydrate metabolism by enhancing insulin signaling, action, and thus the sensitivity of insulin-sensitive tissues. A very likely link between diabetes and obesity is the adipose tissue, which stores energy in the form of triglycerides and releases free fatty acids. To date, there is paucity of information on the exact mechanism of the chromium effect concerning insulin-activated molecular paths, such as adipogenesis. The aim of the present study is to delve into such an effect by employing a well-defined form of chromium (Cr(III)-citrate) on the a) survival of pre- and mature adipocytes (3T3-L1), b) endogenous cell motility, and c) insulin-enhancing adipogenic capacity. The emerging results suggest that Cr(III)-citrate a) is (a)toxic in a concentration- and time-dependent manner, b) has no influence on cell motility, c) can induce 3T3-L1 pre-adipocyte differentiation into mature adipocytes through elevation of tissue specific biomarker levels (PPAR-γ, GLUT 4 and GCK), and d) exemplifies structurally-based metal-induced adipogenesis as a key process contributing to the development of future antidiabetic metallodrugs.
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      PubDate: 2016-07-30T08:53:02Z
       
  • Cobalt(II) complexes of sparfloxacin: Characterization, structure,
           antimicrobial activity and interaction with DNA and albumins
    • Abstract: Publication date: Available online 28 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Eleftherios Kouris, Stavros Kalogiannis, Franc Perdih, Iztok Turel, George Psomas
      The cobalt(II) complexes with the quinolone sparfloxacin (Hsf) in the absence or presence of the nitrogen-donor heterocyclic ligands 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen) or 2,2′-bipyridylamine (bipyam) were prepared and characterized physicochemically and spectroscopically. The crystal structures of complexes [Co(sf)2(bipy)]∙3MeOH·2H2O and [Co(sf)2(phen)]∙4MeOH were determined by X–ray crystallography. The antimicrobial activity of the complexes was tested against four different microorganisms (Escherichia coli, Xanthomonas campestris, Staphylococcus aureus and Bacillus subtilis) and was found similar or higher than that of free Hsf. The binding of the complexes to calf-thymus DNA was monitored by UV spectroscopy and DNA-viscosity measurements and indirectly by competitive studies with ethidium bromide; intercalation is suggested as the most possible interaction mode. Fluorescence emission spectroscopy was used to evaluate the interaction of the complexes with human or bovine serum albumin proteins and the corresponding binding constants were determined.
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      PubDate: 2016-07-30T08:53:02Z
       
  • Effects of histidin-2-ylidene vs. imidazol-2-ylidene ligands on the
           anticancer and antivascular activity of complexes of ruthenium, iridium,
           platinum, and gold
    • Abstract: Publication date: Available online 27 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Florian Schmitt, Kate Donnelly, Julienne K. Muenzner, Tobias Rehm, Vojtech Novohradsky, Viktor Brabec, Jana Kasparkova, Martin Albrecht, Rainer Schobert, Thomas Mueller
      Couples of N-heterocyclic carbene complexes of ruthenium, iridium, platinum, and gold, each differing only in the carbene ligand being either 1,3-dimethylimidazol-2-ylidene (IM) or 1,3-dimethyl-N-boc-O-methylhistidin-2-ylidene (HIS), were assessed for their antiproliferative effect on seven cancer cell lines, their interaction with DNA, their cell cycle interference, and their vascular disrupting properties. In MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays only the platinum complexes were cytotoxic at single-digit micromolar IC50 concentrations with the (HIS)Pt complex being on average twice as active as the (IM)Pt complex. The former was highly efficacious against cisplatin-resistant HT-29 colon carcinoma cells where the latter had no effect. Both Pt complexes were accumulated by cancer cells and bound to double-helical DNA equally well. Only the (HIS)Pt complex modified the electrophoretic mobility of circular DNA in vitro due to the HIS ligand causing greater morphological changes to the DNA. Both platinum complexes induced accumulation of 518A2 melanoma cells in G2/M and S phase of the cell cycle. A disruption of blood vessels in the chorioallantoic membrane of fertilized chicken eggs was observed for both platinum complexes and the (IM)gold complex. The (HIS)platinum complex was as active as cisplatin in tumor xenografted mice while being tolerated better. We found that the HIS ligand may augment the cytotoxicity of certain antitumoral metal fragments in two ways: by acting as a transmembrane carrier increasing the cellular accumulation of the complex, and by initiating a pronounced distortion and unwinding of DNA. We identified a new (HIS)platinum complex which was highly cytotoxic against cancer cells including cisplatin-resistant ones.
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      PubDate: 2016-07-30T08:53:02Z
       
  • Use of Ferrous Iron by Metallo-β-Lactamases
    • Abstract: Publication date: Available online 26 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Samuel T. Cahill, Hanna Tarhonskaya, Anna M. Rydzik, Emily Flashman, Michael A. McDonough, Christopher J. Schofield, Jürgen Brem
      Metallo-β-lactamases (MBLs) catalyse the hydrolysis of almost all β-lactam antibacterials including the latest generation carbapenems and are a growing worldwide clinical problem. It is proposed that MBLs employ one or two zinc ion cofactors in vivo. Isolated MBLs are reported to use transition metal ions other than zinc, including copper, cadmium and manganese, with iron ions being a notable exception. We report kinetic and biophysical studies with the di-iron(II)-substituted metallo-β-lactamase II from Bacillus cereus (di-Fe(II) BcII) and the clinically relevant B1 subclass Verona integron-encoded metallo-β-lactamase 2 (di-Fe(II) VIM-2). The results reveal that MBLs can employ ferrous iron in catalysis, but with altered kinetic and inhibition profiles compared to the zinc enzymes. A crystal structure of di-Fe(II) BcII reveals only small overall changes in the active site compared to the di-Zn(II) enzyme including retention of the di-metal bridging water; however, the positions of the metal ions are altered in the di-Fe(II) compared to the di-Zn(II) structure. Stopped-flow analyses reveal that the mechanism of nitrocefin hydrolysis by both di-Fe(II) BcII and di-Fe(II) VIM-2 is altered compared to the di-Zn(II) enzymes. Notably, given that the MBLs are the subject of current medicinal chemistry efforts, the results raise the possibility the Fe(II)-substituted MBLs may be of clinical relevance under conditions of low zinc availability, and reveal potential variation in inhibitor activity against the differently metallated MBLs.
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      PubDate: 2016-07-30T08:53:02Z
       
  • Insights into the anti-angiogenic properties of phosphaplatins
    • Abstract: Publication date: Available online 27 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Lu Yang, Shadi Moghaddas, Homa Dezvareh, Louiza Belkacemi, Steven J. Bark, Rathindra N. Bose, Loi H. Do
      Phosphaplatins are platinum-based antitumor compounds that, unlike other clinically utilized platinum drugs (i.e. cisplatin, carboplatin, and oxaliplatin), appear to target proteins rather than DNA. Because of their unique mode of action, phosphaplatins are promising drug candidates for cisplatin-resistant cancers. In this study, we discovered that Pt(II) (RRD2) and Pt(IV) (RRD4) phosphaplatins possess diverse antitumor properties. In addition to targeting apoptosis antigen (FAS) and proapoptotic gene products as described previously, RRD2 and RRD4 also target angiogenesis. We demonstrate that RRD2 and RRD4 inhibit human umbilical vein endothelial cell (HUVEC) migration and tube formation in vitro and suppress tumor angiogenesis and growth in immunodeficient mice that were inoculated with A2780 ovarian cancer cells in vivo. To provide insight into this novel antitumor mechanism, phosphaplatin-treated HUVECs were found to exhibit lower gene expression levels of vascular endothelial growth factors (VEGFs) and the VEGFR-2 receptor compared to untreated cells. Kinase inhibition studies suggest that phosphaplatins are inhibitors of VEGFR-2. In ligand exchange experiments using both Pt atomic absorption and 31P NMR spectroscopies, we show that phosphaplatins most likely bind to VEGFR-2 through metal-ligand coordination rather than electrostatic interactions. These studies enhance our understanding of the diverse and novel mechanisms of action of the phosphaplatin antitumor agents, which could potentially be used as chemotherapeutic agents against cisplatin-resistant cancers.
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      PubDate: 2016-07-30T08:53:02Z
       
  • EPR and DFT analysis of biologically relevant chromium(V) complexes with
           d-glucitol and d-glucose
    • Abstract: Publication date: Available online 20 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Sabine Van Doorslaer, Quinten Beirinckx, Kevin Nys, María Florencia Mangiameli, Bert Cuypers, Freddy Callens, Henk Vrielinck, Juan Carlos González
      1,2-diolato ligands, such as carbohydrates and glycoproteins, tend to stabilize chromium(V), thus forming important intermediates that have been implicated in the genotoxicity of Cr(VI). Since many years, room-temperature continuous-wave electron paramagnetic resonance (EPR) at X-band microwave frequencies has been used as a standard characterization tool to study chromium(V) intermediates formed during the reduction of Cr(VI) in the presence of biomolecules. In this work, the added value is tested of using a combination of pulsed and high-field EPR techniques with density functional theory computations to unravel the nature of Cr(V) complexes with biologically relevant chelators, such as carbohydrates. The study focuses on the oxidochromium(V) complexes formed during reduction of potassium dichromate with glutathione in the presence of the monosaccharide d-glucose or the polyalcohol d-glucitol. It is shown that although the presence of a multitude of Cr(V) intermediates may hamper a complete structural determination, the combined EPR and DFT approach reveals unambiguously the effect of freezing on the location of the counterions, the gradual replacement of water ligands by the diols, and the preference of Cr(V) to bind certain conformers.
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      PubDate: 2016-07-26T08:43:46Z
       
  • Impact of cyclometalated ruthenium(II) complexes on lactate dehydrogenase
           activity and cytotoxicity in gastric and colon cancer cells
    • Abstract: Publication date: Available online 26 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Hugo Rico Bautista, Rafael Omar Saavedra Díaz, Longzhu Q. Shen, Christophe Orvain, Christian Gaiddon, Ronan Le Lagadec, Alexander D. Ryabov
      Lactate dehydrogenase (LDH) is a redox enzyme often overexpressed in cancer cells allowing their survival in stressful metabolic tumor environment. Ruthenium(II) complexes have been shown to impact on the activity of purified horseradish peroxidase and glucose oxidase but the physiological relevance remains unclear. In this study we investigated how ruthenium complexes impact on the activity of LDH in vitro and in cancer cells and performed a comparative study using polypyridine ruthenium(II) complex [Ru(bpy)3]2+ (1) and its structurally related cyclometalated 2-phenylpyridinato counterpart [Ru(phpy)(bpy)2]+ (2) (bpy=2,2′-bipyridine, phpyH =2-phenylpyridine). We show that the cytotoxicity in gastric and colon cancer cells induced by 2 is significantly higher compared to 1. The kinetic inhibition mechanisms on purified LDH and the corresponding inhibition constants K i or i 0.5 values were calculated. Though complexes 1 and 2 are structurally very similar (one Ru⎼C bond in 2 replaces one Ru⎼N bond in 1), their inhibition modes are different. Cyclometalated complex 2 behaves exclusively as a non-competitive inhibitor of LDH from rabbit muscle (LDHrm), strongly suggesting that 2 does not interact with LDH in the vicinities of either lactate/pyruvate or NAD+/NADH binding sites. Sites of interaction of 1 and 2 with LDHrm were revealed theoretically through computational molecular docking. Inhibition of LDH activity by 2 was confirmed in cancer cells. Altogether, these results revealed an inhibition of LDH activity by ruthenium complex through a direct interaction structurally tuned by a Ru⎼C bond.
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      PubDate: 2016-07-26T08:43:46Z
       
  • Effective cleavage of phosphodiester promoted by the zinc(II) and
           copper(II) inclusion complexes of β-cyclodextrin
    • Abstract: Publication date: Available online 15 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Ying-Hua Zhou, Li-Qing Chen, Jun Tao, Jun-Li Shen, Dao-Yu Gong, Rui-Rui Yun, Yong Cheng
      To construct the model of metallohydrolase, two inclusion complexes [MLCl2(β-CD)] (1, M=Zn(II); 2, M=Cu(II); L= N,N′-bis(2-pyridylmethyl)amantadine; β-CD=β-cyclodextrin) were synthesized by mixing β-CDs with the pre-synthesized complexes G1, [ZnLCl2] and G2, [CuLCl2]. Structures of G1, G2, 1 and 2 were characterized by X-ray crystallography, respectively. In solution, two chloride anions of G1 and G2 underwent ligand exchange with solvent molecules according to ESI-MS analysis. The chemical equilibrium constants were determined by potentiometric pH titration. The kinetics of bis(4-nitrophenyl) phosphate (BNPP) hydrolysis catalyzed by G1, G2, 1 and 2 were examined at pHs ranging from 7.50 to 10.50 at 308±0.1K. The pH profile of rate constant of BNPP hydrolysis catalyzed by 1 exhibited an exponential increase with the second-order rate constant of 2.68×10−3 M−1 s−1 assigned to the di-hydroxo species, which was approximately an order of magnitude higher than those of reported mono-Zn(II)-hydroxo species. The high reactivity was presumably hydroxyl-rich microenvironment provided by β-CDs, which might effect in stabilizing either the labile zinc-hydroxo species or the catalytic transition state.
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      PubDate: 2016-07-17T06:57:54Z
       
  • Novel silver(I) complexes of coumarin oxyacetate ligands and their
           phenanthroline adducts: Biological activity, structural and spectroscopic
           characterisation
    • Abstract: Publication date: Available online 16 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Muhammad Mujahid, Natasha Trendafilova, Agnieszka Foltyn Arfa-Kia, Georgina Rosair, Kevin Kavanagh, Michael Devereux, Maureen Walsh, Siobhán McClean, Bernadette S. Creaven, Ivelina Georgieva
      Novel silver(I) complexes of coumarin oxyacetate ligands and their phenanthroline adducts have been prepared and characterised by microanalytical data and spectroscopic techniques (IR, 1H, 13C NMR, UV–Vis). The crystal structure of one Ag(I) complex was determined by X-ray diffraction analysis. The experimental spectroscopic data have been interpreted on the basis of molecular structure modeling and subsequent spectra simulation with density functional theory method. The binding modes of the coumarins and phenanthroline ligands (monodentate, bidentate, bridging) to Ag(I) have been theoretically modelled and discussed as to the most probable ligand binding in the series of complexes studied. The antimicrobial and antifungal activities have been determined and the complexes were found to have mostly moderate antibacterial activity but some of the phenanthroline adducts were found to have antifungal activity against the clinically important fungus C. albicans, comparable to that of the commercial agents, Amphotericin B and Ketoconazole. Preliminary investigations into the possible mechanism of action of the silver complexes indicated that they did not interact with DNA via nuclease activity or intercalation but the ability to act as a superoxide dismutase mimetic may be related to their antimicrobial activity.
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      PubDate: 2016-07-17T06:57:54Z
       
  • Kinetic Studies on the Reaction of Cob(II)alamin with Hypochlorous Acid:
           Evidence for one electron oxidation of the metal center and corrin ring
           destruction
    • Abstract: Publication date: Available online 15 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Rohan S. Dassanayake, Mohamed M. Farhath, Jacob T. Shelley, Soumitra Basu, Nicola E. Brasch
      Kinetic and mechanistic studies on the reaction of a major intracellular vitamin B12 form, cob(II)alamin (Cbl(II)), with hypochlorous acid/hypochlorite (HOCl/OCl−) have been carried out. Cbl(II) (Co(II)) is rapidly oxidized by HOCl to predominately aquacobalamin/hydroxycobalamin (Cbl(III), Co(III)) with a second-order rate constant of 2.4 x 107 M−1 s−1 (25.0°C). The stoichiometry of the reaction is 1:1. UHPLC/HRMS analysis of the product mixture of the reaction of Cbl(II) with 0.9mol equiv. HOCl provides support for HOCl being initially reduced to Cl• and subsequent H atom abstraction from the corrin macrocycle occurring, resulting in small amounts of corrinoid species with two or four H atoms fewer than the parent cobalamin. Upon the addition of excess (H)OCl further slower reactions are observed. Finally, SDS-PAGE experiments show that HOCl-induced damage to bovine serum albumin does not occur in the presence of Cbl(II), providing support for Cbl(II) being an efficient HOCl trapping agent.
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      PubDate: 2016-07-17T06:57:54Z
       
  • Design and characterization of highly in vitro antitumor active ternary
           copper(II) complexes containing 2′-hydroxychalcone ligands
    • Abstract: Publication date: Available online 9 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Radka Křikavová, Ján Vančo, Zdeněk Trávníček, Jakub Hutyra, Zdeněk Dvořák
      A series of innovative copper(II) complexes of the general composition [Cu(Ln)(phen)]NO3 (1–8; phen=1,10-phenanthroline), involving 2′-hydroxychalcone {(E)-1-(2′-hydroxyphenyl)-3-phenylprop-2-en-1-one} derivatives (HLn) was synthesized, thoroughly characterized and screened for in vitro cytotoxicity against a panel of ten human cancer cell lines. The most promising results were achieved for complex 2 with the best IC50 value of 1.1±0.7μM (against A2780 cell line). The toxicity testing on a primary culture of human hepatocytes (HH) revealed that complex 2 is the least toxic from the whole series with the IC50 value of 63.7μM. The complexes were shown to be able to efficaciously cleave pUC19 plasmid DNA as well as intercalate into calf thymus DNA with the same affinity and efficacy as ethidium bromide and interact by the ligand exchange mechanism with l-cysteine at physiological concentration levels.
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      PubDate: 2016-07-13T06:37:07Z
       
  • High stability and biological activity of the copper(II) complexes of
           alloferon 1 analogues containing tryptophan
    • Abstract: Publication date: Available online 9 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Agnieszka Kadej, Mariola Kuczer, Elżbieta Czarniewska, Arkadiusz Urbański, Grzegorz Rosiński, Teresa Kowalik-Jankowska
      Complex formation processes between the alloferon 1 (Allo1) (HGVSGHGQHGVHG) analogues where the tryptophan residue is introducing in the place His residue H1W, H6W, H9W and H12W have been studied by potentiometric, UV–visible, CD and EPR spectroscopic, and MS methods. For all analogues of alloferon 1 complex speciation have been obtained for a 1:1 metal-to-ligand molar ratio and 2:1 of H1W because of precipitation at higher (2:1, 3:1 and 4:1) ratios. At physiological pH7.4 and a 1:1 metal-to-ligand molar ratio the tryptophan analogues of alloferon 1 form the CuH−1L and/or CuH−2L complexes with the 4N binding mode. The introduction of tryptophan in place of histidine residues changes the distribution diagram of the complexes formed with the change of pH and their stability constants compared to the respective substituted alanine analogues of alloferon 1. The CuH−1L, CuH−2L and CuH−3L complexes of the tryptophan analogues are more stable from 1 to 5 log units in comparison to those of the alanine analogues. This stabilization of the complexes may result from cation(Cu(II))-π and indole/imidazole ring interactions. The induction of apoptosis in vivo, in Tenebrio molitor cells by the ligands and their copper(II) complexes at pH7.4 was studied. The biological results show that copper(II) ions in vivo did not cause any apparent apoptotic features. The most active were the H12W peptide and Cu(II)-H12W complex formed at pH7.4.
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      PubDate: 2016-07-13T06:37:07Z
       
  • Synthesis, characterization and activity of imidazolate-bridged and
           Schiff-base dinuclear complexes as models of Cu,Zn-SOD. A comparative
           study
    • Abstract: Publication date: Available online 9 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Verónica A. Daier, Eric Rivière, Sonia Mallet-Ladeira, Diego M. Moreno, Christelle Hureau, Sandra R. Signorella
      Two imidazolate-bridged diCuII and CuIIZnII complexes, [CuZn(dien)2(μ-Im)](ClO4)3·MeOH (1) and [Cu2(dien)2(μ-Im)](ClO4)3 (2) (dien=diethylenetriamine), and two complexes formed with Schiff base ligands, [CuZn(salpn)Cl2] (3) and [Cu2(salbutO)ClO4] (4) (H2salpn=1,3-bis(salicylidenamino)propane, H3salbutO=1,4-bis(salicylidenamino)butan-2-ol) have been prepared and characterized. The reaction of [Cu(dien)(ImH)](ClO4)2 with [Zn(dien)(H2O)](ClO4)2 at pH≥11 yields complex 1; at lower pH, the Cu3Zn tetranuclear complex [{(dien)Cu(μ-Im)}3Zn(OH2)(ClO4)2](ClO4)3 (1a) forms as the main reaction product. X-ray diffraction of 1a reveals that the complex contains a metal centered windmill-shaped cation having three blades with a central Zn ion and three peripheral capping Cu(dien) moieties bound to the central Zn ion through three imidazolate bridges. The four complexes are able to disproportionate O2 − in aqueous medium at pH7.8, with relative rates 4 > 1 > 2 ≫ 3. [Cu2(salbutO)]+ (4) is the most easily reducible of the four complexes and exhibits the highest activity among the SOD models reported so far; a fact related to the ligand flexibility to accommodate the copper ion in both CuI and CuII oxidation states and the lability of the fourth coordination position of copper facilitating stereochemical rearrangements.
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      PubDate: 2016-07-13T06:37:07Z
       
  • Ni(II) complexes with 2,2′-dipyridylamine and salicylaldehydes:
           Synthesis, crystal structure and interaction with calf-thymus DNA and
           albumins
    • Abstract: Publication date: Available online 8 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Ariadni Zianna, George Psomas, Antonis Hatzidimitriou, Maria Lalia-Kantouri
      The synthesis of four cationic mixed–ligand Ni(II) complexes with 2,2′–dipyridylamine (dpamH) and substituted salicylaldehydes (X–saloH) was undertaken in an effort to discover new biologically active compounds. The complexes with the general formula [Ni(dpamH)2(X–salo)]Cl, 3–6, namely [Ni(dpamH)2(5–Cl–salo)]Cl, 3, [Ni(dpamH)2(5–Br–salo)]Cl, 4, [Ni(dpamH)2(5–CH3–salo)]Cl, 5, and [Ni(dpamH)2(3–OCH3–salo)]Cl·CH3OH, 6, were characterized by elemental analyses, FT–IR and UV–vis spectroscopy, magnetic and conductivity measurements. In addition, two analogous nickel–salicylaldehydato complexes in the absence of dpamH were prepared and characterized as [Ni(5–Cl–salo)2(CH3OH)2], 1 and [Ni(5–Br–salo)2(CH3OH)2], 2. The structures of complexes 1–6 were determined by X–ray crystallography revealing octahedral coordination of nickel (II) and monomeric nature of the compounds. Spectroscopic (UV–vis), electrochemical (cyclic voltammetry) and physicochemical (viscosity measurements) techniques were employed in order to study the binding mode and strength of the complexes to calf–thymus (CT) DNA, while competitive studies with ethidium bromide (EB), performed by fluorescence spectroscopy, revealed the ability of the complexes to displace the DNA-bound EB. The complexes bind to DNA probably via intercalation exhibiting high DNA–binding constants. For the cationic complexes 3–6, the coexistence of an electrostatic interaction with CT DNA may be also suggested. The interaction of the complexes with serum albumins was studied by fluorescence emission spectroscopy and the determined binding constants exhibit relative high values.
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      PubDate: 2016-07-09T06:22:52Z
       
  • Enhanced anti-cancer activities of a gold(III) pyrrolidinedithiocarbamato
           complex incorporated in a biodegradable metal-organic framework
    • Abstract: Publication date: October 2016
      Source:Journal of Inorganic Biochemistry, Volume 163
      Author(s): Raymond Wai-Yin Sun, Ming Zhang, Dan Li, Mian Li, Alice Sze-Tsai Wong
      An anti-cancer active gold(III) pyrrolidinedithiocarbamato complex [(PDTC)AuIIICl2] (1) has been synthesized and characterized by means of X-ray crystallography. Compared to the pyrrolidinedithiocarbamate ligand itself, this gold(III) complex displays an up to 33-fold higher anti-cancer potency towards a panel of cancer cell lines including the cisplatin-resistant ovarian carcinoma cell line (A2780cis). As demonstrated by a set of Transwell® assay-based cytotoxicity experiments, incorporating this gold(III) complex in a zinc-based biodegradable metal-organic framework (MOF) displays a significant enhancement in anti-cancer activity towards A2780cis than the gold(III) complex alone.
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      PubDate: 2016-07-05T04:56:03Z
       
  • A combined crystallographic analysis and ab initio calculations to
           interpret the reactivity of functionalized hexavanadates and their
           inhibitor potency toward Na+/K+-ATPase
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161
      Author(s): Xiao Xu, Nada Bošnjaković-Pavlović, Mirjana B. Čolović, Danijela Z. Krstić, Vesna M. Vasić, Jean-Michel Gillet, Pingfan Wu, Yongge Wei, Anne Spasojević-de Biré
      In vitro influence of five synthesized functionalized hexavanadates (V6) on commercial porcine cerebral cortex Na+/K+-ATPase activity has been studied. Dose dependent Na+/K+-ATPase inhibition was obtained for all investigated compounds. Calculated half maximal inhibitory concentration IC50 values, in mol/L, for Na+/K+-ATPase were 7.6×10−5, 1.8×10−5, 2.9×10−5, 5.5×10−5 for functionalized hexavanadates (V6) with tetrabutylammonium (TBA) [V6–CH3][TBA]2, [V6–NO2][TBA]2, [V6–OH][TBA]2 and [V6–C3][TBA]2 respectively. [V6–OH][Na]2 inhibited Na+/K+-ATPase activity up to 30% at maximal investigated concentration 1×10−3 mol/L. This reactivity has been interpreted using a study of the non-covalent interactions of functionalized hexavanadate hybrids through Cambridge Structural Database (CSD) analysis. Bibliographic searching has led to 18 different structures and 99 contacts. We have observed that C–H⋯O contacts consolidate the structures. We have also performed density functional theory (DFT) calculations and have determined electrostatic potential values at the molecular surface on a series of functionalized V6. These results enlightened their chemical reactivity and their potential biological applications such as the inhibition of the ATPase.
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      PubDate: 2016-06-17T18:00:43Z
       
  • Behavior of the potential antitumor VIVO complexes formed by flavonoid
           ligands. 3. Antioxidant properties and radical production capability
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161
      Author(s): Daniele Sanna, Valeria Ugone, Angela Fadda, Giovanni Micera, Eugenio Garribba
      The radical production capability and the antioxidant properties of some VIVO complexes formed by flavonoid ligands were examined. In particular, the bis-chelated species of quercetin (que), [VO(que)2]2−, and morin (mor), [VO(mor)2], were evaluated for their capability to reduce the stable radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and produce the hydroxyl radical •OH by Fenton-like reactions, where the reducing agent is VIVO2+. The results were compared with those displayed by other VIVO complexes, such as [VO(H2O)5]2+, [VO(acac)2] (acac=acetylacetonate) and [VO(cat)2]2− (cat=catecholate). The capability of the VIVO flavonoids complexes to reduce DPPH is much larger than that of the VIVO species formed by non-antioxidant ligands and it is due mainly to the flavonoid molecule. Through the 5,5-dimethyl-1-pyrroline N-oxide (DMPO) spin trapping assay of the hydroxyl radical it was possible to demonstrate that in acidic solution VIVO2+ has an effectiveness in producing •OH radicals comparable to that of Fe2+. When VIVO complexes of flavonoids were taken into account, the amount of hydroxyl radicals produced in Fenton-like reactions depends on the specific structure of the ligand and on their capability to reduce H2O2 to give •OH. Both the formation of reactive oxygen species (ROS) under physiological conditions by VIVO complexes of flavonoid ligands and their radical scavenging capability can be put in relationship with their antitumor effectiveness and it could be possible to modulate these actions by changing the features of the flavonoid coordinated to the VIVO2+ ion, such as the entity, nature and position of the substituents and the number of phenolic groups.
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      PubDate: 2016-06-17T18:00:43Z
       
  • Editorial Board
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161




      PubDate: 2016-06-17T18:00:43Z
       
  • Binding properties of ruthenium(II) complexes [Ru(bpy)2(ppn)]2+ and
           [Ru(phen)2(ppn)]2+ with triplex RNA: As molecular “light switches” and
           stabilizers for poly(U)·poly(A)*poly(U) triplex
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161
      Author(s): Jia Li, Yanmei Sun, Zhiyuan Zhu, Hong Zhao, Lifeng Tan
      Stable RNA triplexes play key roles in many biological processes, while triplexes are thermodynamically less stable than the corresponding duplexes due to the Hoogsteen base pairing. To understand the factors affecting the stabilization of RNA triplexes by octahedral ruthenium(II) complexes, the binding of [Ru(bpy)2(ppn)]2+ (1, bpy=2,2′-bipyridine, ppn=2,4-diaminopyrimido[5,6-b]dipyrido[2,3-f:2′,3′-h]quinoxaline) and [Ru(phen)2(ppn)]2+ (2, phen=1,10-phenanthroline) to poly(U)·poly(A)*poly(U) (· denotes the Watson-Crick base pairing and * denotes the Hoogsteen base pairing) has been investigated. The main results obtained here suggest that complexes 1 and 2 can serve as molecular “light switches” and stabilizers for poly(U)·poly(A)*poly(U), while the effectiveness of complex 2 are more marked, suggesting that the hydrophobicity of ancillary ligands has a significant effect on the two Ru(II) complexes binding to poly(U)·poly(A)*poly(U). This study further advances our knowledge on the binding of RNA triplexes with metal complexes, particularly with octahedral ruthenium polypyridyl complexes.
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      PubDate: 2016-06-17T18:00:43Z
       
  • Cytotoxic trans-platinum(II) complex with 3-hydroxymethylpyridine:
           Synthesis, X-ray structure and biological activity evaluation
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161
      Author(s): Sabina Grabner, Barbara Modec, Nataša Bukovec, Peter Bukovec, Maja Čemažar, Simona Kranjc, Gregor Serša, Janez Sčančar
      To assess the potential cytostatic properties of Pt(II) complexes with 3-hydroxymethylpyridine (3-hmpy) as the only carrier ligand, novel cis-[PtCl2(3-hmpy)2] (1) and trans-[PtCl2(3-hmpy)2] (2) have been prepared. Elemental analysis, FTIR spectroscopy, multinuclear NMR spectroscopy and X-ray crystallography were used to determine their structures. Based on the results obtained with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay and clonogenic assay on T24 human bladder carcinoma cells (T24), the most potent compound 2 was further tested for cytotoxicity in human ovarian carcinoma cell lines - cisplatin sensitive (IGROV 1) and its resistant subclone (IGROV 1/RDDP). The cytotoxicity of compound 2 in IGROV 1/RDDP is comparable to cisplatin. Furthermore, compound 2 induced severe conformational changes in plasmid DNA, which resulted in a delayed onset of apoptosis in T24 cells, and higher amounts of Pt in tumours and serum compared to cisplatin. In addition, in vivo antitumour effectiveness was comparable to that of cisplatin with a smaller reduction of animals' body weight, thus demonstrating that it is a promising transplatin analogue which deserves further studies.
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      PubDate: 2016-06-17T18:00:43Z
       
  • Effects of Cu(II) and cisplatin on the stability of Specific protein 1
           (Sp1)-DNA binding: Insights into the regulation of copper homeostasis and
           platinum drug transport
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161
      Author(s): Dong Yan, Isamu Aiba, Helen H.W. Chen, Macus Tien Kuo
      The human high-affinity copper transporter 1 (hCtr1) transports both Cu(I) and cisplatin (cDDP). Because Cu deficiency is lethal yet Cu overload is poisonous, hCtr1 expression is transcriptionally upregulated in response to Cu deficiency but is downregulated under Cu replete conditions in controlling Cu homeostasis. The up- and down-regulation of hCtr1 is regulated by Specific protein 1 (Sp1), which itself is also correspondingly regulated under these Cu conditions. hCtr1 expression is also upregulated by cDDP via upregulation of Sp1. The underlying mechanisms of these regulations are unknown. Using gel-electrophoretic mobility shift assays, we demonstrated here that Sp1-DNA binding affinity is reduced under Cu replete conditions but increased under reduced Cu conditions. Similarly, Sp1-DNA binding affinity is increased by cDDP treatment. This in vitro system demonstrated, for the first time, that regulation of Sp1/hCtr1 expression by these agents is modulated by the stability of Sp1-DNA binding, the first step in the Sp1-mediated transcriptional regulation process.
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      PubDate: 2016-06-17T18:00:43Z
       
  • Synthesis, structural characterization, cytotoxic properties and DNA
           binding of a dinuclear copper(II) complex
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161
      Author(s): B.J.M. Leite Ferreira, P. Brandão, M. Meireles, Fátima Martel, Ana Correia-Branco, Diana M. Fernandes, T.M. Santos, V. Félix
      In this study a novel dinuclear copper(II) complex with adenine and phenanthroline has been synthesized and its structure determined by single crystal X-ray diffraction. In the dinuclear complex [Cu₂(μ-adenine)₂(phen)₂(H2O)2](NO3)4·0.5H2O (phen=1,10-phenanthroline) (1) the two Cu(II) centres exhibit a distorted square pyramidal coordination geometry linked by two nitrogen donors from adenine bridges leading to a Cu–Cu distance of 3.242(3)Å. Intramolecular and intermolecular π⋯π interactions as well as an H-bonding network were observed. The antitumor capacity of the complex has been tested in vitro against human cancer cell lines, cervical carcinoma (HeLa) and colorectal adenocarcinoma (Caco-2), by metabolic tests, using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide as reagent. The complex 1 has remarkable low IC50 values of 0.87±0.06μM (HeLa) and 0.44±0.06μM (Caco-2), when compared with values for cisplatin against the same cell lines. The interaction of complex 1 with calf thymus DNA (CT DNA) was further investigated by absorption and fluorescence spectroscopic methods. A binding constant of 5.09×105 M−1 was obtained from UV–vis absorption studies.
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      PubDate: 2016-06-17T18:00:43Z
       
  • Contents
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161




      PubDate: 2016-06-17T18:00:43Z
       
  • The neglected role of copper ions in wound healing
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161
      Author(s): Allison Paige Kornblatt, Vincenzo Giuseppe Nicoletti, Alessio Travaglia
      Wound healing is a complex biological process that aims to repair damaged tissue. Even though many biological and biochemical mechanisms associated with the steps of physiological wound healing are known, there is still significant morbidity and mortality due to dysregulation of physiological mechanisms. It might be useful to revise the activity of old players and their links with new, often neglected, molecular entities. This review revises new findings supporting the hypothesis that copper ions regulate the activity and/or the expression of proteins crucially involved in the wound repair process. A better understanding of these interactions might suggest potential new targets for therapeutic intervention on scars or non-healing wounds.
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      PubDate: 2016-06-17T18:00:43Z
       
  • Characterization and biological properties of copper(II)-ketoprofen
           complexes
    • Abstract: Publication date: Available online 4 June 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Spyros Perontsis, Antonios G. Hatzidimitriou, Olga-Aggeliki Begou, Athanasios N. Papadopoulos, George Psomas
      From the reaction of Cu(II) with non-steroidal anti-inflammatory drug ketoprofen (Hketo), complex [Cu2(keto)4(H2O)2] was isolated, while the presence of a N,N′-donor heterocyclic ligand 2,2′-bipyridylamine (bipyam), 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy) led to the formation of complexes of the formula [Cu(keto)2(N,N′-donor)(H2O)]. The complexes were characterized by physicochemical and spectroscopic techniques and the crystal structure of [Cu(keto)2(bipyam)(H2O)] was determined by X-ray crystallography. The ability of ketoprofen and its complexes to scavenge 1,1-diphenyl-picrylhydrazyl, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) and hydroxyl radicals was evaluated; the complexes were more active compounds than free Hketo. The interaction of the complexes with serum albumins was investigated by fluorescence emission spectroscopy and the binding constant of the compounds to the albumins were calculated. Diverse techniques including UV spectroscopy, cyclic voltammetry and viscosity measurements as well as fluorescence emission spectroscopy for the competitive studies of the compounds with ethidium bromide, were employed in our attempt to examine the interaction of the compounds with calf-thymus DNA; as a conclusion, intercalation is the most possible mode of binding.
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      PubDate: 2016-06-08T09:57:56Z
       
  • Nickel-diflunisal complexes: synthesis, characterization, in vitro
           antioxidant activity and interaction with DNA and albumins
    • Abstract: Publication date: Available online 4 June 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Spyros Perontsis, Antonios G. Hatzidimitriou, Athanasios N. Papadopoulos, George Psomas
      The reaction of NiCl2 with the non-steroidal anti-inflammatory drug diflunisal (Hdifl) resulted in the formation of complex [Ni(difl-O)2(MeOH)4], 1. The co-existence of a N,N′-donor heterocyclic ligand 2,2′-dipyridylketone oxime (Hpko), 1,10-phenanthroline (phen), 2,2′-bipyridine (bipy) and 2,2′-bipyridylamine (bipyam) led to the formation of complexes [Ni(difl-O)2(Hpko-N,N′)2], 2, [Ni(difl)2(phen)(MeOH)2], 3, [Ni(difl)2(bipy)(MeOH)2], 4 and [Ni(difl-O,O′)2(bipyam)], 5, respectively. The complexes were characterized by physicochemical and spectroscopic techniques and the crystal structures of complexes 1 and 2 were determined by X-ray crystallography. The ability of the complexes to scavenge in vitro 1,1-diphenyl-picrylhydrazyl, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) and hydroxyl radicals was investigated; the complexes were more active scavengers than free Hdifl. The interaction of the complexes with serum albumins was investigated by fluorescence emission spectroscopy and the binding constant of the compounds to the albumins were calculated. UV spectroscopy, cyclic voltammetry and viscosity measurements as well as fluorescence emission spectroscopy for the competitive studies of the complexes with ethidium bromide were employed so as to monitor the interaction of the compounds with calf-thymus DNA and revealed intercalation as the most possible mode of binding.
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      PubDate: 2016-06-08T09:57:56Z
       
  • Vanadium(IV)-chlorodipicolinate inhibits 3T3-L1 preadipocyte adipogenesis
           by activating LKB1/AMPK signaling pathway
    • Abstract: Publication date: Available online 5 June 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Liang Zhang, Ying Huang, Fang Liu, Fang Zhang, Wenjun Ding
      Our previous studies demonstrated that vanadium(IV) complex with 4-chlorodipicolinic acid (VOdipic-Cl) alleviates lipid abnormalities in streptozotocin (STZ)-induced diabetic rats. However, the molecular mechanisms are not fully understood. In the present study, the effect of VOdipic-Cl on adipogenesis and mechanisms of action in 3T3-L1 preadipocytes were investigated. The 3T3-L1 preadipocytes were induced to differentiate in the presence or absence of VOdipic-Cl for 8days. The cells were determined for proliferation, differentiation, lipid accumulation as well as the protein expressions of molecular targets that are involved in fatty acid synthesis. The results demonstrated that VOdipic-Cl at concentrations ranging from 2.5μM to 10μM reduced the intracellular lipid content by 10%, 22% and 30% compared to control. VOdipic-Cl down-regulated the expression of peroxisome proliferator-activated receptor (PPARγ), CCAAT element binding protein a (C/EBPα), sterol regulatory element binding protein 1c (SREBP-1c), fatty acid synthase (FAS) and fatty acid-binding protein 4 (FABP4) and activated the phosphorylation of acetyl coenzyme A carboxylase (ACC), adenosine monophosphate-activated protein kinase (AMPK) and liver kinase B1 (LKB1) in a dose-dependent manner. Further studies showed that AMPK small interfering RNA (siRNA) markedly up-regulated PPARγ, C/EBPα, FAS and FABP4 expression in the presence of VOdipic-Cl, respectively. When LKB1 was silenced with siRNA, the effect of VOdipic-Cl on AMPK phosphorylation was diminished. Taken together, these results suggested that VOdipic-Cl can inhibit 3T3-L1 preadipocyte differentiation and adipogenesis through activating the LKB1/AMPK-dependent signaling pathway. These findings raise the possibility that VOdipic-Cl may be a promising therapy in treatment of obesity.
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      PubDate: 2016-06-08T09:57:56Z
       
  • A comparative study on the interactions of human copper chaperone Cox17
           with anticancer organoruthenium(II) complexes and cisplatin by mass
           spectrometry
    • Abstract: Publication date: Available online 15 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Lijie Li, Wei Guo, Kui Wu, Xuelei Wu, Linhong Zhao, Yao Zhao, Qun Luo, Yuanyuan Wang, Yangzhong Liu, Qingwu Zhang, Fuyi Wang
      Herein we report investigation of the interactions between anticancer organoruthenium complexes, [(η6-arene)Ru(en)(Cl)]PF6 (en=ethylenediamine, arene= p-cymene (1) or biphenyl (2)), and the human copper chaperone protein Cox17 by mass spectrometry with cisplatin as a reference. The electrospray ionization mass spectrometry (ESI-MS) results indicate much weaker binding of the ruthenium complexes than that of cisplatin to apo-Cox172s-s, the functional state of Cox17. Up to tetra-platinated Cox17 adducts were identified while only mono-ruthenated and a little amount of di-ruthenated Cox17 adducts were detected even for the reactions with 10-fold excess of the Ru complexes. However, ESI-MS analysis coupled with liquid chromatography of tryptic digests of metalated proteins identified only three platination sites as Met4, Cys27 and His47 residues, possibly due to the lower abundance or facile dissociation of Pt bindings at other sites. Complexes 1 and 2 were found to bind to the same three residues with Met4 as the major site. Inductively coupled plasma mass spectrometry results revealed that ~7mol Pt binding to 1mol apo-Cox172s-s molecules, compared to only 0.17 (1) and 0.10 (2) mol Ru to 1mol apo-Cox172s-s. This is in line with the circular dichroism results that much larger unfolding extent of α-helix of apo-Cox172s-s was observed upon cisplatin binding than that upon organoruthenium bindings. These results collectively indicate that Cox17 might not participate in the action of these anticancer organoruthenium complexes, and further verify the distinct anticancer mechanism of the organoruthenium(II) complexes from cisplatin.
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      PubDate: 2016-05-19T05:11:26Z
       
  • G-quadruplex vs. duplex-DNA binding of nickel(II) and zinc(II) Schiff base
           complexes
    • Abstract: Publication date: Available online 14 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Riccardo Bonsignore, Alessio Terenzi, Angelo Spinello, Annamaria Martorana, Antonino Lauria, Anna Maria Almerico, Bernhard K. Keppler, Giampaolo Barone
      Novel nickel(II) (1) and zinc(II) (2) complexes of a Salen-like ligand, carrying a pyrimidine ring on the N,N′ bridge, were synthesized and characterized. Their interaction with duplex and G-quadruplex DNA was investigated in aqueous solution through UV–visible absorption, circular dichroism and viscometry measurements. The results obtained point out that, while the zinc(II) complex does not interact with both duplex and G-quadruplex DNA, the nickel(II) complex 1 binds preferentially to G-quadruplex respect to duplex-DNA, with values of the DNA-binding constants, K b , 2.6✕105 M−1 and 3.5✕104 M−1, respectively. Molecular dynamics simulations provided an atomic level model of the top-stacking binding occurring between 1 and hTelo G-quadruplex.
      Graphical abstract image

      PubDate: 2016-05-19T05:11:26Z
       
  • High kinetic stability of ZnII coordinated by the tris(histidine) unit of
           carbonic anhydrase towards solvolytic dissociation studied by affinity
           capillary electrophoresis
    • Abstract: Publication date: Available online 17 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Yosuke Sato, Hitoshi Hoshino, Nobuhiko Iki
      Solvolytic dissociation rate constants (k d) of bovine carbonic anhydrase II (CA) and its metallovariants (M-CAs, M=CoII, NiII, CuII, ZnII, and CdII) were estimated by a ligand substitution reaction, which was monitored by affinity capillary electrophoresis to selectively detect the undissociated CAs in the reaction mixture. Using EDTA as the competing ligand for Zn-CA, the dissociation followed the unimolecular nucleophilic substitution (SN1) mechanism with k d =1.0×10−7 s−1 (pH7.4, 25°C). The corresponding solvolysis half-life (t 1/2) was 80days, showing the exceptionally high kinetic stability of t Zn-CA, in contrast to the highly labile [ZnII(H2O)6]2+, where the water exchange rate (k ex) is high. This behavior is attributed to the tetrahedral coordination geometry supported by the tris(histidine) unit (His3) of CA. In the case of Co-CA, it showed a somewhat larger k d value (5.7×10−7 s−1, pH7.4, 25°C) even though it shares the same tetrahedral coordination environment with Zn-CA, suggesting that the d 7 electronic configuration of CoII in the transition state of the dissociation is stabilized by the ligand field. Among M-CAs, only Ni-CA showed a bimolecular nucleophilic substitution (SN2) reaction path in its reaction with EDTA, implying that the large coordination number (6) of NiII in Ni-CA allows EDTA to form an EDTA-Ni-CA intermediate. Overall, k d values roughly correlated with k ex values among M-CAs, with the k d value of Zn-CA deviating strongly from the trend and highlighting the exceptionally high kinetic stabilization of Zn-CA by the His3 unit.
      Graphical abstract image

      PubDate: 2016-05-19T05:11:26Z
       
  • Revised stability constant, spectroscopic properties and binding mode of
           Zn(II) to FluoZin-3, the most common zinc probe in life sciences
    • Abstract: Publication date: Available online 13 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): I. Marszałek, A. Krężel, W. Goch, I. Zhukov, I. Paczkowska, W. Bal
      2-[2-[2-[2-[bis(carboxylatomethyl)amino]-5-methoxyphenoxy]ethoxy]-4-(2,7-difluoro-3-oxido-6-oxo-4a,9a-dihydroxanthen-9-yl)anilino]acetate (FluoZin-3) is used very broadly in life sciences as intra- and extracellular Zn(II) sensor selective for Zn(II) over Co(II), Ca(II) and Mg(II) ions at their physiological concentrations. It has been used for determination of relative and absolute levels of exchangeable Zn(II) in cells and extracellular fluids. Despite its popularity, the knowledge of its acid/base and Zn(II) coordination abilities and of its spectroscopic properties remained very limited. Also the published conditional dissociation constant (C K d) values at pH7.4 are slightly discrepant, (15nM or 8.9nM). In this work we determined the C K d for Zn(II) complexation by FluoZin-3 at pH7.4 with nitrilotriacetic acid (NTA) as competitor using two independent methods: fluorimetry and UV–Vis spectroscopy. For the first time, we investigated FluoZin-3 alone and complexed with Zn(II) in the wide range of pH, determining the total of eight pK a values from fluorescence spectra and from various regions of UV–Vis spectra. The validated values of C K d (9.1±0.4nM; −log C K d =8.04) and of the absolute (pH-independent) stability constant log βZnL (8.16±0.05) were provided by fluorescence spectroscopy experiments performed at 1μM concentrations. Our experiments demonstrated that both of aminocarboxylate moieties of FluoZin-3 bind the Zn(II) ion synergistically.
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      PubDate: 2016-05-14T04:43:16Z
       
  • The (unusual) aspartic acid in the metal coordination sphere of the
           prokaryotic zinc finger domain
    • Abstract: Publication date: Available online 11 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Gianluca D'Abrosca, Luigi Russo, Maddalena Palmieri, Ilaria Baglivo, Fortuna Netti, Ivan de Paola, Laura Zaccaro, Biancamaria Farina, Rosa Iacovino, Paolo Vincenzo Pedone, Carla Isernia, Roberto Fattorusso, Gaetano Malgieri
      The possibility of choices of protein ligands and coordination geometries leads to diverse Zn(II) binding sites in zinc-proteins, allowing a range of important biological roles. The prokaryotic Cys2His2 zinc finger domain (originally found in the Ros protein from A. tumefaciens) tetrahedrally coordinates zinc through two cysteine and two histidine residues and it does not adopt a correct fold in the absence of the metal ion. Ros is the first structurally characterized member of a family of bacterial proteins that presents several amino acid changes in the positions occupied in Ros by the zinc coordinating residues. In particular, the second position is very often occupied by an aspartic acid although the coordination of structural zinc by an aspartate in eukaryotic zinc fingers is very unusual. Here, by appropriately mutating the protein Ros, we characterize the aspartate role within the coordination sphere of this family of proteins demonstrating how the presence of this residue only slightly perturbs the functional structure of the prokaryotic zinc finger domain while it greatly influences its thermodynamic properties.
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      PubDate: 2016-05-14T04:43:16Z
       
  • Targeting copper(II)-induced oxidative stress and the acetylcholinesterase
           system in Alzheimer's disease using multifunctional tacrine-coumarin
           hybrid molecules
    • Abstract: Publication date: Available online 5 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Slavka Hamulakova, Patrik Poprac, Klaudia Jomova, Vlasta Brezova, Peter Lauro, Lenka Drostinova, Daniel Jun, Vendula Sepsova, Martina Hrabinova, Ondrej Soukup, Pavol Kristian, Zuzana Gazova, Zuzana Bednarikova, Kamil Kuca, Marian Valko
      Alzheimer's disease is a multifactorial disease that is characterized mainly by Amyloid-β (A-β) deposits, cholinergic deficit and extensive metal (copper, iron)-induced oxidative stress. In this work we present details of the synthesis, antioxidant and copper-chelating properties, DNA protection study, cholinergic activity and amyloid-antiaggregation properties of new multifunctional tacrine-7-hydroxycoumarin hybrids. The mode of interaction between copper(II) and hybrids and interestingly, the reduction of Cu(II) to Cu(I) species (for complexes Cu-5e-g) were confirmed by EPR measurements. EPR spin trapping on the model Fenton reaction, using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trap, demonstrated a significantly suppressed formation of hydroxyl radicals for the Cu-5e complex in comparison with free copper(II). This suggests that compound 5e upon coordination to free copper ion prevents the Cu(II)-catalyzed decomposition of hydrogen peroxide, which in turn may alleviate oxidative stress-induced damage. DNA damage protection activity of hybrids 5c and 5e in a Fenton system (copper catalyzed) was found to be in excellent agreement with the EPR spin trapping study. Compound 5g was the most effective in the inhibition of acetylcholinesterase (hAChE, IC 50 =38nM) and compound 5b was the most potent inhibitor of butyrylcholinesterase (hBuChE, IC 50 =63nM). Compound 5c was the strongest inhibitor of A-β1–40 aggregation, although a significant inhibition (>50%) was detected for compounds 5b, 5d, 5e and 5g. Collectively, these results suggest that the design and investigation of multifunctional agents containing along with the acetylcholinesterase inhibitory segment also an antioxidant moiety capable of alleviating metal (copper)-induced oxidative stress, may be of importance in the treatment of Alzheimer's disease.
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      PubDate: 2016-05-09T06:06:59Z
       
  • Synthesis, characterization and antitumoral activity of new
           cobalt(II)complexes: effect of the ligand isomerism on the biological
           activity of the complexes
    • Abstract: Publication date: Available online 8 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Samila R. Morcelli, Érika Stilobezzia bulla, Wagner S. Terra, Rafaela O. Moreira, Franz V. Borges, Milton M. Kanashiro, Adailton J. Bortoluzzi, Leide L.F. Maciel, João Carlos de A. Almeida, Adolfo Horn Júnior, Christiane Fernandes
      The synthesis, physico-chemical characterization and cytotoxicity against five human tumoral cell lines (THP-1, U937, Molt-4, Colo205 and H460) of three new cobalt(II) coordination compounds are reported (i.e. Co(HL1)Cl (1), Co(HL2)Cl (2) and [Co(HL3)Cl]0.0.5 (CH3)2CHOH (3)). H2L2 (2-{[[2-hydroxy-3-(1-naphthyloxy)propyl](pyridin-2-ylmethyl)amino]methyl}phenol) and H2L3 (2-{[[2-hydroxy-3-(2-naphthyloxy)propyl](pyridin-2-ylmethyl)amino]methyl}phenol) present α and β-naphthyl groups respectively, which is absent in H2L1 (N-(2-hydroxybenzyl)-N-(2-pyridylmethyl)[(3-chloro)(2-hydroxy)]propylamine.These compounds were characterized by a range of physico-chemical methods. X-ray diffraction studies were performed for complex (3), indicating the formation of a mononuclear complex. Complexes (2) and (3), which contain α and β-naphthyl groups respectively, have presented lower IC50 values than those exhibited by complex (1). Complex (3) presents IC50 values lower than cisplatin against Colo205 (90 and 196 μmol L−1, respectively) and H460 (147 and 197 μmol L−1, respectively). These human neoplastic cells under investigation were also more susceptible toward complex (3) than peripheral blood mononuclear cells. Transmission electron microscopy investigations are in agreement with the loss of mitochondrial membrane potential (ΔΨm) observed by JC-1 mitochondrial potential sensor and indicate that the activity of complex (3) against leukemic cell line (U937) is mediated by an apoptotic mechanism associated with mitochondrial dysfunction (intrinsic pathway).
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      PubDate: 2016-05-09T06:06:59Z
       
  • Metals content of Glossoscolex paulistus extracellular hemoglobin: Its
           peroxidase activity and the importance of these ions in the protein
           stability
    • Abstract: Publication date: Available online 5 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Celia S. Caruso, Ezer Biazin, Francisco A.O. Carvalho, Marcel Tabak, José F.R. Bachega
      In this work we investigate the presence of divalent cations bound to the Glossoscolex paulistus (HbGp) hemoglobin and their effect over the protein stability and the peroxidase (POD) activity. Atomic absorption studies show that the HbGp iron content is consistent with the presence of 144 ions per protein. Moreover, using iron as a reference, the content of calcium was estimated as 30±4 ions per protein, independently of the EDTA pre-treatment or not prior to the acidic treatment performed in the protein digestion. The zinc content was 14±2 ions in the absence of EDTA pre-treatment, and 3±1 ions per protein in the presence of EDTA pre-treatment, implying the presence of one zinc ion per protomer (1/12 of the whole molecule). Finally, the copper concentration is negligible. Different from the vertebrate hemoglobins, where the effectors are usually organic anions, the hexagonal bilayer hemoglobins have as effectors inorganic cations that increase the oxygen affinity and stabilize the structure. Previous studies have suggested that the presence of divalent cations, such as copper and zinc, is related to the different types of antioxidant enzymatic activities as the superoxide dismutase (SOD) activity shown by giant hemoglobin from Lumbricus terrestris (HbLt). Recently, studies on HbGp crystal structure have confirmed the presence of Zn2+ and Ca2+ binding sites. The Ca2+ sites are similar as observed in the HbLt crystal structure. Otherwise, the Zn2+ sites have no relation with those observed in Cu/Zn SODs. Our peroxidase assays with guaiacol confirm the POD activity and the effect of the zinc ions for HbGp. Our present results on HbGp metal content and their stability effects is the first step to understand the role of these cations in HbGp function in the future.
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      PubDate: 2016-05-09T06:06:59Z
       
  • Surface complex of ZnTMPyP4 metalloporphyrin with double-stranded
           poly(a)-poly(U)
    • Abstract: Publication date: Available online 6 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): G. Tolstykh, V. Sizov, A. Kudrev
      This communication presents synthesis and spectral characterization of metalloporphyrin [Zn(X)TMPyP4] (TMPyP4 is 5,10,15,20-tetrakis (N-methylpyridinium-4-yl)porphyrin), and studies its binding onto anionic surface sites of synthetic double stranded polynucleotide Poly(A)-Poly(U). [Zn(X)TMPyP4] binding with Poly(A)-Poly(U) was monitored by UV–Vis absorbance spectroscopy, two fluorescence spectroscopies and 1H NMR in a working aqueous medium of 0.15M ionic strength, pH7.0 and at 25°C. The evidence provided by spectroscopic measurements and multivariate data analysis suggests the use of this metalloporphyrin as a probe for investigation of the polynucleotide surface. In contrast to TMPyP4 intercalation, an outside adsorption of [Zn(X)TMPyP4] induces an attenuation of luminescence intensity and has little influence on the shape of luminescence band. Special attention was paid to the quantitative description of the interaction between neighboring ligands on the Poly(A)-Poly(U) surface. The intrinsic binding constant to an isolated binding site lgKin 5.8±0.1, the cooperativity parameter ω 1.8±0.2, and number of monomers occupied by a ligand n =2 (25°C; pH7.0) were calculated based upon the recently proposed non-linear least-squares fitting procedure. The discovered cooperativity of binding of [Zn(X)TMPyP4] metalloporphyrin to Poly(A)-Poly(U) is significantly lower as compared to free porphyrin TMPyP4, reflecting minimal mutual influence between the nearest neighboring ligands bound with functional PO4 − groups of the polynucleotide surface.
      Graphical abstract image

      PubDate: 2016-05-09T06:06:59Z
       
 
 
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