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  Subjects -> CHEMISTRY (Total: 825 journals)
    - ANALYTICAL CHEMISTRY (47 journals)
    - CHEMISTRY (575 journals)
    - CRYSTALLOGRAPHY (22 journals)
    - ELECTROCHEMISTRY (26 journals)
    - INORGANIC CHEMISTRY (41 journals)
    - ORGANIC CHEMISTRY (46 journals)
    - PHYSICAL CHEMISTRY (68 journals)

INORGANIC CHEMISTRY (41 journals)

Acta Polymerica     Hybrid Journal   (Followers: 6)
Additives for Polymers     Full-text available via subscription   (Followers: 21)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 4)
Advances in Polymer Technology     Hybrid Journal   (Followers: 11)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 2)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 4)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal  
Current Methods in Inorganic Chemistry     Full-text available via subscription  
European Journal of Inorganic Chemistry     Hybrid Journal   (Followers: 6)
European Polymer Journal     Hybrid Journal   (Followers: 41)
Heterocyclic Communications     Full-text available via subscription   (Followers: 2)
High Performance Polymers     Hybrid Journal  
Indian Journal of Chemistry - Section A     Open Access   (Followers: 5)
Inorganic Chemistry     Full-text available via subscription   (Followers: 19)
Inorganic Chemistry Communications     Hybrid Journal   (Followers: 7)
Inorganic Chemistry Frontiers     Full-text available via subscription  
Inorganic Materials     Hybrid Journal   (Followers: 2)
Inorganic Materials: Applied Research     Hybrid Journal   (Followers: 1)
Inorganica Chimica Acta     Hybrid Journal   (Followers: 4)
Inorganics     Open Access  
International Journal of Inorganic Chemistry     Open Access   (Followers: 1)
JBIC Journal of Biological Inorganic Chemistry     Hybrid Journal   (Followers: 2)
Journal of Inorganic and Organometallic Polymers and Materials     Partially Free   (Followers: 6)
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 2)
Journal of Inorganic Chemistry     Open Access  
Journal of Polymer Engineering     Full-text available via subscription   (Followers: 9)
Journal of Polymers and the Environment     Hybrid Journal   (Followers: 3)
Journal of Separation Science     Hybrid Journal   (Followers: 7)
Metallodrugs     Open Access  
Open Journal of Inorganic Chemistry     Open Access   (Followers: 1)
Plasmas and Polymers     Hybrid Journal  
Polymer Bulletin     Hybrid Journal   (Followers: 7)
Polymer Composites     Hybrid Journal   (Followers: 8)
Polyoxometalate Chemistry     Open Access  
Reviews in Inorganic Chemistry     Full-text available via subscription  
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: 3)
Topics in Inorganic and General Chemistry     Full-text available via subscription  
Zeitschrift für anorganische und allgemeine Chemie     Hybrid Journal   (Followers: 1)
Zeitschrift für Kristallographie - New Crystal Structures     Open Access  
Journal Cover   Journal of Inorganic Biochemistry
  [SJR: 0.96]   [H-I: 87]   [4 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0162-0134
   Published by Elsevier Homepage  [2586 journals]
  • Hypoglycemic, lipid-lowering and metabolic regulation activities of
           metforminium decavanadate (H2Met)3 [V10O28] • 8H2O using
           hypercaloric-induced carbohydrate and lipid deregulation in wistar rats as
           biological model
    • Abstract: Publication date: Available online 10 April 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Samuel Treviño , Eduardo Sánchez-Lara , Víctor Enrique Sarmiento-Ortega , Irma Sánchez Lombardo , José Ángel Flores-Hernández , Aarón Pérez-Benítez , Eduardo Brambila Colombres , Enrique González-Vergara
      Because of the increasing global spread of type 2 Diabetes Mellitus, there is a need to develop new antidiabetic agents. Recently we have synthesized new decavanadates using metformin as counterion. In particular, the compound containing three metforminium dications has been obtained in high yield and has been completely characterized. Biological studies using Wistar rats that have been fed with a high caloric diet inducing insulin resistance and metabolic syndrome were carried out. Results of the impact on key biochemical parameters mediated by metformin alone and the new compound are here presented. The metforminium decavanadate (H2Met)3[V10O28]∙8H2O, abbreviated as Metf-V10O28, was shown to have pharmacological potential as a hypoglycemic, lipid-lowering and metabolic regulator, since the resultig compound made of the two components with antidiabetic activities, reduce both dosage and time of administration (twice a week). Hence, due to the beneficial effects induced by the metforminium decavanadate we recommend to continue exploration into the mechanism and toxicology of this new compound.
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      PubDate: 2015-04-16T08:58:51Z
       
  • (Aminophosphane)gold(I) and silver(I) complexes as antibacterial agents
    • Abstract: Publication date: May 2015
      Source:Journal of Inorganic Biochemistry, Volume 146
      Author(s): Lourdes Ortego , Jesús Gonzalo-Asensio , Antonio Laguna , M. Dolores Villacampa , M. Concepción Gimeno
      This manuscript describes the synthesis of new Au(I) and Ag(I) complexes with aminophosphane ligands and a study of their antibacterial activity against Gram-negative Salmonella enterica serovar typhimurium and Escherichia coli and Gram-positive Listeria monocytogenes and Staphylococcus aureus. The bactericidal assays revealed the effectiveness of these compounds on paradigm Gram-negative and Gram-positive pathogens, showing a moderate antimicrobial activity, comparable with the antibiotics of reference, for all gold(I) complexes and the silver(I) complexes without coordinated PPh3 groups. For those complexes that were found to show inhibitory activity, serial dilutions in liquid broth method were performed for determination of MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration).
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      PubDate: 2015-04-16T08:58:51Z
       
  • Selective nuclei accumulation of ruthenium(II) complex enantiomers that
           target G-quadruplex DNA
    • Abstract: Publication date: Available online 11 April 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Dongdong Sun , Yanan Liu , Qianqian Yu , Du Liu , Yanhui Zhou , Jie Liu
      Different enantiomers exhibit large differences in their biological activity and/or toxicity, but they rarely involve the relationship of the agents for molecular and cellular imaging with the chiral structure of ruthenium complexes. Here, we report that an enantiomer of a polypyridyl ruthenium complex can selectively accumulate in the nucleus of HepG2 cells. Confocal laser scanning microscopy studies show that this phenomenon occurs via a non-endocytotic, but temperature-dependent, mechanism of cellular uptake in HepG2 cells. DNA oligonucleotides with repetitive tracts of guanine bases that can form G-quadruplex structures have aroused interest as therapeutic agents and as targets for anticancer drug design. Various biophysical techniques show that the Λ-enantiomer of ruthenium complexes can selectively stabilize human telomeric G-quadruplex DNA and has a strong preference for G-quadruplex over duplex DNA. Judged from the NMR results, we speculate that at higher 4:1 ligand /G-quadruplex stoichiometry, complex Λ-Ru is likely to bind with each groove of the tetraplex in a dimeric form or intercalate with the G-tetrad in the 3′ terminal face and coexist with other modes. The molecular modeling analysis is in agreement with the NMR titrations performed in this investigation indicating that ruthenium complexes are actually characterized by a mixed binding mode. The results provide many opportunities for the development of novel agents for living cell-related studies.


      PubDate: 2015-04-16T08:58:51Z
       
  • Photoinduced reduction of the medial FeS center in the hydrogenase small
           subunit HupS from Nostoc punctiforme
    • Abstract: Publication date: Available online 14 April 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Patrícia Raleiras , Leif Hammarström , Peter Lindblad , Stenbjörn Styring , Ann Magnuson
      The small subunit from the NiFe uptake hydrogenase, HupSL, in the cyanobacterium Nostoc punctiforme ATCC29133, has been isolated in the absence of the large subunit (P. Raleiras, P. Kellers, P. Lindblad, S. Styring, A. Magnuson, J. Biol. Chem. 288 (2013) 18345–18352). Here, we have used flash photolysis to reduce the iron sulfur clusters in the isolated small subunit, HupS. We used ascorbate as electron donor to the photogenerated excited state of Ru(II)-trisbipyridine (Ru(bpy)3), to generate Ru(I)(bpy)3 as reducing agent. Our results show that the isolated small subunit can be reduced by the Ru(I)(bpy)3 generated through flash photolysis.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Complexes of N-hydroxyethyl-N-benzimidazolylmethylethylenediaminediacetic
           acid with group 12 metals and vanadium – synthesis, structure and
           bioactivity of the vanadium complex
    • Abstract: Publication date: Available online 11 April 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Ladislav Habala , Caroline Bartel , Gerald Giester , Michael A. Jakupec , Bernhard K. Keppler , Annette Rompel
      Four new complexes of group 12 metals [Zn(II), Cd(II) and Hg(II)], along with vanadyl bound to the ligand N-hydroxyethyl-N-benzimidazolylmethylethylenediaminediacetic acid, have been synthesized and characterized. The structure of the complexes with Zn(II), Hg(II) and V(IV) was determined by X-ray structural analysis. In all observed cases, the symmetry of these complexes was found to be distorted octahedral. The inhibition of protein tyrosine phosphatase 1B by the vanadium(IV) complex was demonstrated. The cytotoxicity of the vanadium(IV) complex was tested in vitro against three cancer cell lines, with a comparison of the activity of the free ligand and of vanadyl acetylacetonate and sodium orthovanadate. The IC50 values of the complex were in the range of 9 to 21 μM. Remarkably, cytotoxic potency in the multidrug-resistant non-small cell lung cancer cell line A549 was at least as high as in the broadly chemosensitive ovarian teratocarcinoma cell line CH1(PA-1).
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      PubDate: 2015-04-16T08:58:51Z
       
  • Controlling diabetes by chromium complexes: The role of the ligands
    • Abstract: Publication date: May 2015
      Source:Journal of Inorganic Biochemistry, Volume 146
      Author(s): Mei Peng , Xiaoping Yang
      Diabetes, particularly type II diabetes, is a severe disease condition which affects human health worldwide, with a dramatically increasing trend in Asian countries including China. Currently, no efficient drugs other than those with observable side effects are available. Chromium complexes, with the most known representative chromium picolinate, have been listed as one of most attractive health supplements to attenuate this disease condition in western countries. Recent efforts have been made to develop new chromium complexes with novel ligands. Although fair amounts of reviews have been published to emphasize the biological activity, preclinical and clinical information of chromium picolinate, this mini-review is trying to cover the entire picture of updated research efforts on various chromium complexes highlighting the role of ligands. Chromium phenylalanine sensitizes insulin cell signaling pathway via the activation of phosphorylation of Akt (protein kinase B (PKB)) and/or AMPK (AMP-activated protein kinase). The biological activities, toxicity, pharmacological features and clinical implications, including the effect of anti-oxidative capacities, protective effect on obese-induced heart dysfunction, and efficacy and safety of chromium supplementation in diabetes are discussed as well.
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      PubDate: 2015-04-16T08:58:51Z
       
  • A ruthenium(II) complex inhibits tumor growth in vivo with fewer
           side-effects compared with cisplatin
    • Abstract: Publication date: May 2015
      Source:Journal of Inorganic Biochemistry, Volume 146
      Author(s): Jin-Quan Wang , Ping-Yu Zhang , Liang-Nian Ji , Hui Chao
      The antitumor activity of a ruthenium(II) polypyridyl complex, Δ-[Ru(bpy)2(HPIP)](ClO4)2 (Δ-Ru1, where bpy=2,2′-bipyridine, HPIP=2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline), was evaluated. The in vivo experiments showed that Δ-Ru1 inhibited the growth of a human cervical carcinoma cell line (HeLa) xenotransplanted into nude mice with efficiency similar to that of cisplatin. Histopathology examination of the tumors from treated xenograft models was consistent with apoptosis in tumor cells. Importantly, in striking contrast with cisplatin, Δ-Ru1 did not cause any detectable side effects on the kidney, liver, peripheral neuronal system, or the hematological system at the pharmacologically effective dose. The preclinical studies reported here provide support for the clinical use of Δ-Ru1 as an exciting new drug candidate with lower toxicity than cisplatin, endowed with proapoptotic properties.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Synthesis, characterization, hydrolase and catecholase activity of a
           dinuclear iron(III) complex: Catalytic promiscuity
    • Abstract: Publication date: May 2015
      Source:Journal of Inorganic Biochemistry, Volume 146
      Author(s): Tiago P. Camargo , Fernanda F. Maia , Cláudia Chaves , Bernardo de Souza , Adailton J. Bortoluzzi , Nathalia Castilho , Tiago Bortolotto , Hernán Terenzi , Eduardo E. Castellano , Wolfgang Haase , Zbigniew Tomkowicz , Rosely A. Peralta , Ademir Neves
      Herein, we report the synthesis and characterization of the new di-iron(III) complex [(bbpmp)(H2O)(Cl)FeIII(μ-Ophenoxo)FeIII(H2O)Cl)]Cl (1), with the symmetrical ligand 2,6-bis{[(2-hydroxybenzyl)(pyridin-2-yl)methylamino]methyl}-4-methylphenol (H3bbpmp). Complexes 2 with the unsymmetrical ligand H2bpbpmp — {2-[[(2-hydroxybenzyl)(2-pyridylmethyl)]aminomethyl]-6-bis(pyridylmethyl) aminomethyl}-4-methylphenol and 3 with the ligand L1 =4,11-dimethyl-1,8-bis{2-[N-(di-2-pyridylmethyl)amino]ethyl}cyclam were included for comparison purposes. Complex 1 was characterized through elemental analysis, X-ray crystallography, magnetochemistry, electronic spectroscopy, electrochemistry, mass spectrometry and potentiometric titration. The magnetic data show a very weak antiferromagnetic coupling between the two iron centers of the dinuclear complex 1 (J =−0.29cm−1). Due to the presence of labile coordination sites in both iron centers the hydrolysis of both the diester model substrate 2,4-BDNPP and DNA was studied in detail. Complex 1 was also able to catalyze the oxidation of the substrate 3,5-di-tert-butylcatechol (3,5-DTBC) to give the corresponding quinone, and thus it can be considered as a catalytically promiscuous system.
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      PubDate: 2015-04-16T08:58:51Z
       
  • A new mononuclear manganese(III) complex of an unsymmetrical hexadentate
           N3O3 ligand exhibiting superoxide dismutase and catalase-like activity:
           synthesis, characterization, properties and kinetics studies
    • Abstract: Publication date: May 2015
      Source:Journal of Inorganic Biochemistry, Volume 146
      Author(s): Gabriela N. Ledesma , Hélène Eury , Elodie Anxolabéhère-Mallart , Christelle Hureau , Sandra R. Signorella
      A mononuclear MnIII complex MnL·4H2O (H3L=1-[N-(2-pyridylmethyl),N-(2-hydroxybenzyl)amino]-3-[N′-(2-hydroxybenzyl),N′-(4-methylbenzyl)amino]propan-2-ol) has been prepared and characterized. This complex catalyzes the dismutation of superoxide efficiently, with catalytic rate constant kcat =1.7×106 M−1 s−1 and IC 50 1.26μM, obtained through the nitro blue tetrazolium photoreduction inhibition superoxide dismutase assay, in aqueous solution of pH7.8. MnL is also able to disproportionate more than 300 equivalents of H2O2 in CH3CN, with initial rate of H2O2 decomposition given by ri = kcat [MnL]2 [H2O2] and kcat =1.32(2)mM−2 min−1. The accessibility of the MnIV state (E p =0.53V vs. saturated calomel electrode), suggests MnL employs a high-valent catalytic cycle to decompose O2 − and H2O2.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Hypobromous acid, a powerful endogenous electrophile: Experimental and
           theoretical studies
    • Abstract: Publication date: May 2015
      Source:Journal of Inorganic Biochemistry, Volume 146
      Author(s): Valdecir Farias Ximenes , Nelson Henrique Morgon , Aguinaldo Robinson de Souza
      Hypobromous acid (HOBr) is an inorganic acid produced by the oxidation of the bromide anion (Br−). The blood plasma level of Br− is more than 1,000-fold lower than that of chloride anion (Cl−). Consequently, the endogenous production of HOBr is also lower compared to hypochlorous acid (HOCl). Nevertheless, there is much evidence of the deleterious effects of HOBr. From these data, we hypothesized that the reactivity of HOBr could be better associated with its electrophilic strength. Our hypothesis was confirmed, since HOBr was significantly more reactive than HOCl when the oxidability of the studied compounds was not relevant. For instance: anisole (HOBr, k2 =2.3×102 M−1 s−1, HOCl non-reactive); dansylglycine (HOBr, k2 =7.3×106 M−1 s−1, HOCl, 5.2×102 M−1 s−1); salicylic acid (HOBr, k2 =4.0×104 M−1 s−1, non-reactive); 3-hydroxybenzoic acid (HOBr, k2 =5.9×104 M−1 s−1, HOCl, k2 =1.1×101 M−1 s−1); uridine (HOBr, k2 =1.3×103 M−1 s−1, HOCl non-reactive). The compounds 4-bromoanisole and 5-bromouridine were identified as the products of the reactions between HOBr and anisole or uridine, respectively, i.e. typical products of electrophilic substitutions. Together, these results show that, rather than an oxidant, HOBr is a powerful electrophilic reactant. This chemical property was theoretically confirmed by measuring the positive Mulliken and ChelpG charges upon bromine and chlorine. In conclusion, the high electrophilicity of HOBr could be behind its well-established deleterious effects. We propose that HOBr is the most powerful endogenous electrophile.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Association of structural modifications with bioactivity in three new
           copper(II) complexes of Schiff base ligands derived from
           5-chlorosalicylaldehyde and amino acids
    • Abstract: Publication date: May 2015
      Source:Journal of Inorganic Biochemistry, Volume 146
      Author(s): Ang Li , Ya-Hong Liu , Ling-Zhi Yuan , Zhong-Ying Ma , Chun-Lai Zhao , Cheng-Zhi Xie , Wei-Guo Bao , Jing-Yuan Xu
      Three novel structurally associated copper(II) complexes [CuII(SalCl-Gly)(H2O)2] (1), [CuII(SalCl-Ala)(H2O)] (2) and [CuII(SalCl-Gly)(bipy)]·0.5H2O (3) (SalCl-Gly=5-chloro-2-hydroxybenzylidene-glycine, SalCl-Ala=5-chloro-2-hydroxybenzylidene-alanine, bipy=2,2′-bipyridine) have been synthesized and characterized by X-ray crystallography, elemental analysis, IR and fluorescence spectroscopy. Single-crystal diffraction reveals that complex 1 is an infinite 1D zigzag chain in which SalCl-Gly serves as both a chelating and a bridging ligand, while complexes 2 and 3 are mononuclear. Cu(II) ions in complexes 1–3 exhibit distorted quasi-hexacoordinated octahedral, tetracoordinated square planar, and pentacoordinated square pyramid geometry, respectively. Their interactions with calf thymus DNA (CT-DNA) have been investigated by viscosity measurements and fluorescence spectroscopy. The apparent binding constant (K app) values for 1–3 are 1.02×105, 0.98×105 and 1.57×105 M−1, respectively. All complexes displayed efficient oxidative cleavage of supercoiled DNA in the presence of H2O2. Complex 2, whose ligand can be regarded as a methyl-modification of SalCl-Gly of 1, showed a reduced DNA cleavage activity and a little-changed DNA-binding ability compared with 1. While attaching a 2,2′-bipyridine group to 1, the resulting complex 3 was conferred an enhanced intercalation into DNA. Moreover, cytotoxicity studies of three complexes against HepG-2 (human liver hepatocellular carcinoma) and NCI-H460 (human large-cell lung carcinoma) cells indicated that, thereto, complex 3 possessed the highest inhibition on viability of tested cells.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Quantification of bindings of organometallic ruthenium complexes to
           GSTπ by mass spectrometry
    • Abstract: Publication date: May 2015
      Source:Journal of Inorganic Biochemistry, Volume 146
      Author(s): Yu Lin , Yongdong Huang , Wei Zheng , Kui Wu , Qun Luo , Yao Zhao , Shaoxiang Xiong , Fuyi Wang
      Electrospray ionization mass spectrometry (ESI-MS) has been widely used to identify binding sites of metal complexes to proteins. However, the MS quantification of the metal–protein coordination remains a challenge. We have recently demonstrated by ESI-MS analysis that organometallic ruthenium complexes [(η6-arene)Ru(en)Cl]+ (arene= p-cymene (1), biphenyl (2) or 9,10-dihydrophenanthrene (3); en=ethylenediamine) bound to human glutathione-S-transferase π (GSTπ) at Cys15 and Cys48 within the G-site, and Cys102 and Met92 on the interface of the GSTπ dimer, showing inhibitory potency against the enzyme (J. Inorg. Biochem., 128 (2013) 77–84). Herein, we developed a mass spectrometric method to quantify the binding stoichiometry of the three complexes to GSTπ. The differences in signal intensities of the heavy-labelled peptides produced by tryptic digestion of the ruthenated GSTπ complexes and the respective light-labelled peptides in the tryptic digest of equimolar GSTπ were used to calculate the binding stoichiometry at specific residues. The results indicated that the pre-complexation of GSTπ with its substrate GSH significantly reduced the bindings of the ruthenium complexes at Met92 and Cys102, but had little impact on the bindings at Cys15 and Cys48. As the inhibitory activities of the ruthenium complexes against GSTπ are similar to those against GSTπ in complexation with GSH, these results suggest that the inhibition of the ruthenium complexes on GSTπ is attributed to the ruthenation at Cys15 and Cys48. The present work provides not only insights into the understanding on the inhibitory mechanism of ruthenium complexes GSTπ, but also a general method for quantitative characterization of metal–protein interactions.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Platinated oligomers of bovine pancreatic ribonuclease: Structure and
           stability
    • Abstract: Publication date: May 2015
      Source:Journal of Inorganic Biochemistry, Volume 146
      Author(s): Delia Picone , Federica Donnarumma , Giarita Ferraro , Irene Russo Krauss , Andrea Fagagnini , Giovanni Gotte , Antonello Merlino
      The reaction between cis-diamminedichloroplatinum(II) (CDDP), cisplatin, a common anticancer drug, and bovine pancreatic ribonuclease (RNase A), induces extensive protein aggregation, leading to the formation of one dimer, one trimer and higher oligomers whose yields depend on cisplatin/protein ratio. Structural and functional properties of the purified platinated species, together with their spontaneous dissociation and thermally induced denaturation, have been characterized. Platinated species preserve a significant, although reduced, ribonuclease activity. The high resistance of the dimers against dissociation and the different thermal unfolding profiles suggest a quaternary structure different from those of the well-known swapped dimers of RNase A.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Europium-doped Gd2O3 nanotubes cause the necrosis of primary mouse bone
           marrow stromal cells through lysosome and mitochondrion damage
    • Abstract: Publication date: May 2015
      Source:Journal of Inorganic Biochemistry, Volume 146
      Author(s): Yi Jin , Shizhu Chen , Jianlei Duan , Guang Jia , Jinchao Zhang
      With the wide applications of europium-doped Gd2O3 nanoparticles (Gd2O3:Eu3+ NPs) in biomedical fields, it will inevitably increase the chance of human exposure. It was reported that Gd2O3:Eu3+ NPs could accumulate in bone. However, there have been few reports about the potential effect of Gd2O3:Eu3+ NPs on bone marrow stromal cells (BMSCs). In this study, the Gd2O3:Eu3+ nanotubes were prepared and characterized by powder X-ray diffraction (XRD), photoluminescence (PL) excitation and emission spectra, scanning electron microscope (SEM), and transmission electron microscopy (TEM). The cytotoxicity of Gd2O3:Eu3+ nanotubes on BMSCs and the associated mechanisms were further studied. The results indicated that they could be uptaken into BMSCs by an energy-dependent and macropinocytosis-mediated endocytosis process, and primarily localized in lysosome. Gd2O3:Eu3+ nanotubes effectively inhibited the viability of BMSCs in concentration and time-dependent manners. A significant increase in the percentage of late apoptotic/necrotic cells, lactate dehydrogenase (LDH) leakage and the number of PI-stained cells was found after BMSCs were treated by 10, 20, and 40μg/mL of Gd2O3:Eu3+ nanotubes for 12h. No obvious DNA ladders were detected, but a dispersed band was observed. The above results revealed that Gd2O3:Eu3+ nanotubes could trigger cell death by necrosis instead of apoptosis. Two mechanisms were involved in Gd2O3:Eu3+ nanotube-induced BMSCs necrosis: lysosomal rupture and release of cathepsins B; and the overproduction of reactive oxygen species (ROS) injury to the mitochondria and DNA. The study provides novel evidence to elucidate the toxicity mechanisms and may be beneficial to more rational applications of these nanomaterials in the future.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Design, synthesis and anticancer activity of diam(m)ine platinum(II)
           complexes bearing a small-molecular cell apoptosis inducer dichloroacetate
           
    • Abstract: Publication date: May 2015
      Source:Journal of Inorganic Biochemistry, Volume 146
      Author(s): Weiping Liu , Jing Jiang , Yongping Xu , Shuqian Hou , Liping Sun , Qingsong Ye , Liguang Lou
      Four new diam(m)ine platinum complexes containing the dichloroacetate moiety in 3-dichoroacetoxylcyclobutane-1,1-dicarboxylate as the leaving group were synthesized, characterized by elemental analysis as well as by ESI+-MS (electrospray ionization mass spectrometry in positive mode), FT-IR, 1H- and 13C-NMR, and evaluated for their in vitro anticancer activity against human lung cancer cell line (A549) and ovarian cancer cell lines (SK-OV-3, SK-OV-3/DDP). Diam(m)ines used in the present study belong to the carriers of six clinically approved platinum drugs. Among the complexes synthesized, complex 2, cis-[Pt(II)(1R,2R-diaminocyclohexane)·(3-dichoroacetoxylcyclobutane-1,1-dicarboxylate)] is the most promising in terms of water solubility and potential of being totally devoid of cross-drug resistance with cisplatin. Therefore, complex 2 was selected for the dichloroacetate release test. The test shows dichloroacetate can be efficiently released from complex 2 under physiological conditions via the hydrolysis of an ester bond bridging the dichloroacetate moiety and platinum pharmacophores together. Our study supports the further evaluation of this complex as a drug candidate.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Macrophage and colon tumor cells as targets for a binuclear silver(I)
           N-heterocyclic carbene complex, an anti-inflammatory and apoptosis
           mediator
    • Abstract: Publication date: May 2015
      Source:Journal of Inorganic Biochemistry, Volume 146
      Author(s): Muhammad Adnan Iqbal , Muhammad Ihtisham Umar , Rosenani A. Haque , Mohamed B. Khadeer Ahamed , Mohd Zaini Bin Asmawi , Amin Malik Shah Abdul Majid
      Chronic inflammation intensifies the risk for malignant neoplasm, indicating that curbing inflammation could be a valid strategy to prevent or cure cancer. Cancer and inflammation are inter-related diseases and many anti-inflammatory agents are also used in chemotherapy. Earlier, we have reported a series of novel ligands and respective binuclear Ag(I)–NHC complexes (NHC= N-heterocyclic carbene) with potential anticancer activity. In the present study, a newly synthesized salt (II) and respective Ag(I)–NHC complex (III) of comparable molecular framework were prepared for a further detailed study. Preliminarily, II and III were screened against HCT-116 and PC-3 cells, wherein III showed better results than II. Both the compounds showed negligible toxicity against normal CCD-18Co cells. In FAM-FLICA caspase assay, III remarkably induced caspase-3/7 in HCT-116 cells most probably by tumor necrosis factor-alpha (TNF-α) independent intrinsic pathway and significantly inhibited in vitro synthesis of cytokines, interleukin-1 (IL-1) and TNF-α in human macrophages (U937 cells). In a cell-free system, both the compounds inhibited cyclooxygenase (COX) activities, with III being more selective towards COX-2. The results revealed that III has strong antiproliferative property selectively against colorectal tumor cells which could be attributed to its pro-apoptotic and anti-inflammatory abilities.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Editorial Board
    • Abstract: Publication date: May 2015
      Source:Journal of Inorganic Biochemistry, Volume 146




      PubDate: 2015-04-16T08:58:51Z
       
  • Contents
    • Abstract: Publication date: May 2015
      Source:Journal of Inorganic Biochemistry, Volume 146




      PubDate: 2015-04-16T08:58:51Z
       
  • Preorganization of the catalytic Zn2+-binding site in the HNH nuclease
           motif – a solution study
    • Abstract: Publication date: Available online 9 April 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Eszter Németh , Milan Kožíšek , Gabriella K. Schilli , Béla Gyurcsik
      The structure of the active site in a metalloenzyme can be a key determinant of its metal ion binding affinity and catalytic activity. In this study, the conformational features of the Zn2+-binding HNH motif were investigated by CD-spectroscopy in combination with isothermal microcalorimetric titrations. Various point mutations, including T454A, K458A and W464A, were introduced into the N-terminal loop of the nuclease domain of colicin E7 (NColE7). We show that the folding of the proteins was severely disturbed by the mutation of the tryptophan residue. This points to the importance of W464, being a part of the hydrophobic core located close to the HNH-motif. ITC demonstrated that the Zn2+-binding of the mutants including the W464 site became weak, and according to CD-spectroscopic measurements the addition of the metal ion itself can not fully recover the functional structure. Titrations with Zn2+-ion in the presence and absence of the Im7 protein proved that the structural changes in the unfolded mutant included the HNH-motif itself. The metal-binding of the NColE7 mutants could be, however, fully rescued by the complexation of Im7. This suggests that the formation of a preorganized metal-binding site – existing in the wild-type enzyme but not in the W464 mutants – was induced by Im7. The low nuclease activity of all W464A mutants, however, implies that the interactions of this tryptophan residue are required for precise location of the catalytic residues, i.e. for stabilization of the fine-structure and of the tertiary structure. Our results contribute to the understanding of the metal binding site preorganization.
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      PubDate: 2015-04-16T08:58:51Z
       
  • The bacteriohemerythrin from Methylococcus capsulatus (Bath): Crystal
           structures reveal that Leu114 regulates a water tunnel
    • Abstract: Publication date: Available online 9 April 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Kelvin H.-C. Chen , Phimonphan Chuankhayan , Hsin-Hui Wu , Chun-Jung Chen , Mitsuhiro Fukuda , Steve S.-F. Yu , Sunney I. Chan
      The bacteriohemerythrin (McHr) from Methylococcus capsulatus (Bath) is an oxygen carrier that serves as a transporter to deliver O2 from the cytosol of the bacterial cell body to the particulate methane monooxygenase residing in the intracytoplasmic membranes for methane oxidation. Here we report X-ray protein crystal structures of the recombinant wild type (WT) McHr and its L114A, L114Y and L114F mutants. The structure of the WT reveals a possible water tunnel in the McHr that might be linked to its faster autoxidation relative to hemerythrin in marine invertebrates. With Leu114 positioned at the end of this putative water tunnel, the hydrophobic side chain of this residue seems to play a prominent role in controlling the access of the water molecule required for autoxidation. This hypothesis is examined by comparing the autoxidation rates of the WT McHr with those of the L114A, L114Y and L114F mutants. The biochemical data are correlated with structural insights derived from the analysis of the putative water tunnels in the various McHr proteins provided by the X-ray structures.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Vanadium(V) and -(IV) Complexes of Anionic Polysaccharides: Controlled
           Release Pharmaceutical Formulations and Models of Vanadium
           Biotransformation Products
    • Abstract: Publication date: Available online 7 April 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Lauren E. Kremer , Andrew I. McLeod , Jade B. Aitken , Aviva Levina , Peter A. Lay
      Uncontrolled reactions in biological media are a main obstacle for clinical translation of V-based anti-diabetic or anti-cancer pro-drugs. We investigated the use of controlled-release pharmaceutical formulations to ameliorate this issue with a series of V(V) and (IV) complexes of anionic polysaccharides. Carboxymethyl cellulose, xanthan gum, or alginic acid formulations were prepared by the reactions of [VO4]3− with one or two molar equivalents of biological reductants, L-ascorbic acid (AA) or L-cysteine (Cys), in the presence of excess polysaccharide at pH ~ 7 or pH ~ 4. XANES studies with the use of a previously developed library of model V(V), V(IV) and V(III) complexes showed that reactions in the presence of AA led mostly to the mixtures of five- and six-coordinate V(IV) species, while the reactions in the presence of Cys led predominantly to the mixtures of five- and six-coordinate V(V) species. The XANES spectra of some of these samples closely matched those reported previously for [VO4]3− biotransformation products in isolated blood plasma, red blood cells, or cultured adipocytes, which supports the hypothesis that modified polysaccharides are major binders of V(V) and V(IV) in biological systems. Studies by EPR spectroscopy suggested predominant V(IV)-carboxylato binding in complexes with polysaccharides. One of the isolated products (a V(IV)-alginato complex) showed selective release of low-molecular-mass V species at pH ~ 8, but not at pH ~ 2, which makes it a promising lead for the development of V-containing formulations for oral administration that are stable in the stomach, but release the active ingredient in the intestines.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Editorial board
    • Abstract: Publication date: April 2015
      Source:Journal of Inorganic Biochemistry, Volume 145




      PubDate: 2015-04-16T08:58:51Z
       
  • Contents
    • Abstract: Publication date: April 2015
      Source:Journal of Inorganic Biochemistry, Volume 145




      PubDate: 2015-04-16T08:58:51Z
       
  • Sulfur and selenium antioxidants: Challenging radical scavenging
           mechanisms and developing structure–activity relationships based on
           metal binding
    • Abstract: Publication date: April 2015
      Source:Journal of Inorganic Biochemistry, Volume 145
      Author(s): Matthew T. Zimmerman , Craig A. Bayse , Ria R. Ramoutar , Julia L. Brumaghim
      Because sulfur and selenium antioxidants can prevent oxidative damage, numerous animal and clinical trials have investigated the ability of these compounds to prevent the oxidative stress that is an underlying cause of cardiovascular disease, Alzheimer's disease, and cancer, among others. One of the most common sources of oxidative damage is metal-generated hydroxyl radical; however, very little research has focused on determining the metal-binding abilities and structural attributes that affect oxidative damage prevention by sulfur and selenium compounds. In this review, we describe our ongoing investigations into sulfur and selenium antioxidant prevention of iron- and copper-mediated oxidative DNA damage. We determined that many sulfur and selenium compounds inhibit CuI-mediated DNA damage and that DNA damage prevention varies dramatically when FeII is used in place of CuI to generate hydroxyl radical. Oxidation potentials of the sulfur or selenium compounds do not correlate with their ability to prevent DNA damage, highlighting the importance of metal coordination rather than reactive oxygen species scavenging as an antioxidant mechanism. Additional gel electrophoresis, mass spectrometry, and UV–visible studies confirmed sulfur and selenium antioxidant binding to CuI and FeII. Ultimately, our studies established that both the hydroxyl-radical-generating metal ion and the chemical environment of the sulfur or selenium significantly affect DNA damage prevention and that metal coordination is an essential mechanism for these antioxidants.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Synthetic, potentiometric and spectroscopic studies of chelation between
           Fe(III) and 2,5-DHBA supports salicylate-mode of siderophore binding
           interactions
    • Abstract: Publication date: April 2015
      Source:Journal of Inorganic Biochemistry, Volume 145
      Author(s): Suheel K. Porwal , Emilia Furia , Michael E. Harris , Rajesh Viswanathan , L. Devireddy
      Catecholate type enterobactin, a prototype siderophore, comprises 2,3-dihydroxybenzoic acid (2,3-DHBA) cyclically linked to serine in E. coli. The existence of iron-chelating ligands in humans is a recent discovery, however, the basic chemical interactions between 2,5-dihydroxybenzoic acid and Fe(III) ion remain poorly understood. Achieving an accurate description of the fundamental Fe(III) binding properties of 2,5-DHBA is essential for understanding its role in iron transport mechanisms. Here, we show that 2,5-DHBA binds iron in a salicylate mode via a two-step kinetic mechanism by UV spectroscopy. Complexation between Fe(III) salt and 2,5-DHBA initially occurs at 1:1 ratio (of ligand to metal) and binding resulting in higher-order complexes continues at higher concentrations. Through potentiometric measurements we quantify the distribution of Fe(III)-2,5-DHBA complexes with 1:1, 1:2 and 1:3 stoichiometry. The formation of 1:3 complexes is further supported through high-resolution mass spectrometry. Further, using kinetic and equilibrium UV spectroscopy, we report Fe(III)-2,5-DHBA complex formation at a pH range of 2.5–9.0 at 298.15K in water. Maximum complexation occurred at a pH range of 4.5–6.5 consistent with deprotonation of the carboxylic acid proton. Equilibrium measurements and stopped-flow kinetics show that complexation rate constants were independent of concentrations of 2,5-DHBA. Together the data supports a model in which the rate-determining step involves rearrangement of ligands on an initial complex formed by reversible binding between the carboxylate group of 2,5-DHBA and Fe(III).
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      PubDate: 2015-04-16T08:58:51Z
       
  • pH-metric chemical speciation modeling and studies of in vitro
           antidiabetic effects of bis[(imidazolyl)carboxylato]oxidovanadium(IV)
           complexes
    • Abstract: Publication date: April 2015
      Source:Journal of Inorganic Biochemistry, Volume 145
      Author(s): Isaac Z. Gundhla , Ryan S. Walmsley , Vital Ugirinema , Nandipha O. Mnonopi , Eric Hosten , Richard Betz , Carminita L. Frost , Zenixole R. Tshentu
      A range of bidentate N,O-donor ligands of the imidazolyl-carboxylate moiety, which partially mimic naturally occurring bioligands, were prepared and reacted with the oxidovanadium(IV) ion to form the corresponding bis-coordinated oxidovanadium(IV) complexes. The aqueous pH-metric chemical speciation was investigated using glass electrode potentiometry, which allowed for the determination of protonation and stability constants of the ligands and complexes, respectively. The species distribution diagrams generated from this information gave evidence that the bis[(imidazolyl)carboxylato]oxovanadium(IV) complexes possess a broad pH-metric stability. The complexes improved glucose uptake in cell cultures using 3T3-L1 adipocytes, C2C12 muscle cells and Chang liver cells. The PTP inhibition studies indicated that the mechanism underlying insulin-stimulated glucose uptake was possibly via the protein tyrosine phosphorylation through the inhibition of the protein tyrosine phosphatase 1B (PTP 1B). The vanadium compounds also demonstrated the inhibition of D-dimer formation, suggesting that these compounds could potentially relieve a hypercoagulative state in diabetic patients.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Bio-relevant cobalt(II) complexes with compartmental polyquinoline ligand:
           Synthesis, crystal structures and biological activities
    • Abstract: Publication date: April 2015
      Source:Journal of Inorganic Biochemistry, Volume 145
      Author(s): Jun-Ling Li , Lin Jiang , Bi-Wei Wang , Jin-Lei Tian , Wen Gu , Xin Liu , Shi-Ping Yan
      Three new Co(II) complexes, [Co4(L)2(μ 3-CrO4)2](ClO4)2 ·2CH3CN (1), [Co2(L)(μ 2-na)(H2O)](ClO4)2 (2) and [Co2(L)(μ 2-ba)](ClO4)2 ·0.5CH3CN (3) (Hna=nicotinic acid, Hba=benzoic acid, HL = N,N,N′,N′-tetrakis (2-quinolylmethyl)-1,3-diaminopropan-2-ol), have been synthesized and characterized by various physicochemical techniques. The Co(II) centers are connected by endogenous alkoxy bridge from L− and various extrinsic auxiliary linkers, some of which display coordination number asymmetry (5, 6-coordinated for 1 and 2; 5, 5-coordinated for 3). It is worth mentioning that complex 1 contains two rare reported μ 3-η 1, η 1, η 1-CrO4 2− moieties. Susceptibility data of three complexes indicated intramolecular antiferromagnetic coupling of high-spin Co(II) atoms with exchange integral values (J) −14.94cm−1, −11.26cm−1 and −13.66cm−1 for 1, 2 and 3, respectively. Interaction of compounds with calf thymus DNA (CT-DNA) have been investigated by absorption spectral titration, ethidium bromide (EB) displacement assay and viscosity measurement, which revealed that compounds bound to CT-DNA with a moderate intercalative mode, accompanied the affinities order: 1 > 2 ≈ 3. Three complexes exhibit oxidative cleavage of pBR322 plasmid DNA including a reliance on H2O2 as the activator. Compound 1 demonstrates an increased DNA cleavage activity as compared with 2 and 3, which could degrade super coiled DNA (SC DNA) into nicked coiled DNA (NC DNA) in lower concentration (5μM). Moreover, all compounds could quench the intrinsic fluorescence of bovine serum albumin (BSA) in a static quenching process. Complex 1 also shows higher anticancer activity than cisplatin with lower IC50 value of incubation for both 24h and 48h.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Synthesis and characterization of water-soluble, heteronuclear
           ruthenium(III)/ferrocene complexes and their interactions with
           biomolecules
    • Abstract: Publication date: April 2015
      Source:Journal of Inorganic Biochemistry, Volume 145
      Author(s): Craig M. Anderson , Swapan S. Jain , Lisa Silber , Kody Chen , Sumedha Guha , Wancong Zhang , Emily C. McLaughlin , Yongfeng Hu , Joseph M. Tanski
      The reaction of Na[RuCl4(SO(CH3)2)2], 1, with one equivalent of FcCONHCH2C6H4N (Fc=FeC10H9), L1, FcCOOCH2CH2C3H3N2, L2, FcCOOC6H4N, L3, afforded the dinuclear species, Na[FcCONHCH2C6H4N[RuCl4(SO(CH3)2)]], RuL1, Na[FcCOOCH2CH2C3H3N2[RuCl4(SO(CH3)2)]], RuL2, Na[FcCOOC6H4N(RuCl4(SO(CH3)2))], RuL3, respectively, yielding, in each case, a ferrocene moiety bridged to a ruthenium center. The complexes were characterized by NMR, IR, and XRD (X-ray diffraction). The sulfoxide ligands are bonded to the metal through the sulfur atom. The complexes were evaluated for their biological activity with pBluescript DNA plasmid, and the protein BSA (bovine serum albumin). These reactions were monitored by XAS (X-ray absorption spectroscopy), EXAFS (extended X-ray Absorption Fine Structure), NMR, UV/visible, emission spectroscopy, and gel electrophoresis. Donor atoms from the biomolecules substitute for the chloride ligands in the parent complexes.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Quercetin encapsulation in modified silica nanoparticles: potential use
           against Cu(II)-induced oxidative stress in neurodegeneration
    • Abstract: Publication date: April 2015
      Source:Journal of Inorganic Biochemistry, Volume 145
      Author(s): Christiane M. Nday , Eleftherios Halevas , Graham E. Jackson , Athanasios Salifoglou
      Neurodegenerative diseases entail deeply complex processes, intimately associated with progressive brain damage reflecting cellular demise. Biochemical reactivity linked to such processes in Alzheimer’s disease involves, among others, metal-induced oxidative stress contributing to neuronal cell death. Prominent among redox active metals inducing oxidative stress is Cu(II). Poised to develop molecular technology counteracting oxidative stress, efforts were launched to prepare bioactive hybrid nanoparticles, capable of working as host-carriers of potent antioxidants, such as the natural flavonoid quercetin. Employing synthetic protocols consistent with the assembly of silica nanoparticles, PEGylated and CTAB-modified materials were synthesized. Subsequent concentration-dependent loading of quercetin led to well-defined molecular carriers, the antioxidant efficiency of which was determined through drug release studies using UV-visible spectroscopy. The physicochemical characterization (elemental analysis, particle size, z-potential, FT-IR, thermogravimetric analysis, scanning electron microscopy) of the empty and loaded silica nanoparticles led to the formulation of optimized material linked to the delivery of the encapsulated antioxidant to primary rat hippocampal cultures under oxidative stress. Entrapment and drug release studies showed a) the competence of hybrid nanoparticles as far as the loading capacity in quercetin (concentration dependence), b) congruence with the physicochemical features determined, and c) the release profile of the nanoparticle load under oxidative stress in neuronal cultures. The bio-activity profile of quercetin nanoparticles in a neurodegenerative environment brought on by Cu(II) a) denotes the improved specificity of antioxidant reactivity counteracting oxidative stress, and b) sets the stage for the development of molecular protection and preventive medical nanotechnology of relevance to neurodegenerative Alzheimer’s disease.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Insight on the interaction of an agmatinase-like protein with Mn2+
           activator ions
    • Abstract: Publication date: April 2015
      Source:Journal of Inorganic Biochemistry, Volume 145
      Author(s): Matías Quiñones , Jaime Cofre , José Benítez , David García , Nicol Romero , Arlette González , Nelson Carvajal , María García , Vasthi López , Gerhard Schenk , Elena Uribe
      Agmatinase is an enzyme that catalyzes the hydrolysis of agmatine, a compound that is associated with numerous functions in the brain of mammalian organisms such as neurotransmitter, anticonvulsant, antinociceptive, anxiolytic and antidepressant-like actions. To date the only characterized agmatinases with significant enzymatic activity were extracted from bacterial organisms. These agmatinases are closely related to another ureahydrolase, arginase; both have binuclear Mn2+ centers in their active sites. An agmatinase-like protein (ALP) from rat brain was identified that bears no sequence homology to known agmatinases (E. Uribe, M. Salas, S. Enriquez, M.S. Orellana, N. Carvajal, Arch. Biochem. Biophys. 461(2007) 146–150). Since all known ureahydrolases contain histidines in their binuclear Mn2+ site each of the five histidine residues in ALP was individually replaced by alanines to identify those that may be involved in metal ion binding. Reactivation assays and thermal stability measurements indicated that His206 is likely to interact with a Mn2+ bound to a high affinity site. In contrast, His65 and possibly His435 are important for binding of a second Mn2+ to a lower affinity site. Metal ion binding to that site is not only leading to an increase in reactivity but also enzyme stability. Thus, similar to bacterial agmatinases and some of the antibiotic-degrading, Zn2+-dependent metallo-β-lactamases ALP appears to be active in the mono and binuclear form, with binding of the second metal ion increasing both reactivity and stability.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Chromium speciation and biochemical changes vary in relation to plant
           ploidy
    • Abstract: Publication date: April 2015
      Source:Journal of Inorganic Biochemistry, Volume 145
      Author(s): Jozef Kováčik , Bořivoj Klejdus , Petr Babula , Maria Elisa Soares , Josef Hedbavny , Maria de Lourdes Bastos
      Uptake of trivalent chromium (Cr(III)-chloride), Cr speciation and consequences for the metabolism in chamomile plants with two ploidy levels have been studied. Depletion of fresh biomass, tissue water content and soluble proteins in response to high (120μM) Cr(III) was ploidy-independent. Cr mainly accumulated in the roots (only negligibly in the shoots) and total root Cr amount was higher in tetraploid ones including the proof with specific fluorescent indicator (naphthalimide–rhodamine) of Cr(III). Quantification of Cr(VI) detected its higher content in tetraploid roots (up to 4.2% from total Cr), indicating partial oxidation of applied Cr(III). Higher H2O2 presence but lower activities of peroxidases were observed in tetraploid roots while nitric oxide, superoxide dismutase and glutathione reductase activities did not differ extensively. Soluble phenols, lignin, non-protein thiols, individual thiols (glutathione and phytochelatin 2) and ascorbic acid responded to high Cr(III) similarly in both cultivars while decrease of minerals was more pronounced in tetraploid ones. It seems that Cr(III)-induced oxidative stress arises from high root Cr uptake and Cr(VI) presence and is related to depletion of thiols. Assay of Krebs cycle acids confirmed rather depletion under 120μM Cr(III) in both cultivars but increase in citric acid may indicate its involvement in root Cr chelation. Subsequent comparison of Cr(III)-chloride and Cr(III)-nitrate showed similar influence on Cr accumulation and majority of biochemical responses while different impact on phytochelatin 2 amount was the most distinct feature.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Synthesis, structure and biological activity of nickel(II) complexes with
           mefenamato and nitrogen-donor ligands
    • Abstract: Publication date: April 2015
      Source:Journal of Inorganic Biochemistry, Volume 145
      Author(s): Xanthippi Totta , Aikaterini A. Papadopoulou , Antonios G. Hatzidimitriou , Athanasios Papadopoulos , George Psomas
      Six novel nickel(II) complexes with the non-steroidal anti-inflammatory drug mefenamic acid (Hmef) with the nitrogen-donor heterocyclic ligands 2,2′-bipyridine (bipy), 2,2′-bipyridylamine (bipyam), 1,10-phenanthroline (phen), 2,2′-dipyridylketone oxime (Hpko) or pyridine (py) and/or the oxygen-donor ligands CH3OH or H2O were synthesized and characterized by physicochemical and spectroscopic techniques. The crystal structures of [Ni(mef-O)2(bipy)(CH3OH)2] (1), [Ni(mef-O)2(phen)(CH3OH)2] (2), [Ni(mef-O,O′)2(bipyam)] (3) and [Ni(mef-O)2(Hpko)2]∙CH3OH (4·CH3OH) were determined by X-ray crystallography. The ability of the complexes to scavenge 1,1-diphenyl-picrylhydrazyl, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) and hydroxyl radicals was investigated and the in vitro inhibitory activity against soybean lipoxygenase was evaluated; complexes 3 and 4 were the most active compounds. Spectroscopic (UV and fluorescence), electrochemical (cyclic voltammetry) and physicochemical (viscosity measurements) techniques were employed in order to study the binding mode of the complexes to calf-thymus (CT) DNA and to calculate the corresponding binding constants; for all complexes, intercalation was the most possible mode of DNA-binding. The interaction of the complexes with serum albumins was studied by fluorescence emission spectroscopy and the values of the albumin-binding constants were determined.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Synthesis, structural studies and biological activity of new Cu(II)
           complexes with acetyl derivatives of 7-hydroxy-4-methylcoumarin
    • Abstract: Publication date: April 2015
      Source:Journal of Inorganic Biochemistry, Volume 145
      Author(s): Marcin T. Klepka , Aleksandra Drzewiecka-Antonik , Anna Wolska , Paweł Rejmak , Kinga Ostrowska , Elżbieta Hejchman , Hanna Kruszewska , Agnieszka Czajkowska , Izabela Młynarczuk-Biały , Wiesława Ferenc
      The new Cu(II) complexes with 6-acetyl-7-hydroxy-4-methylcoumarin (HL1) and 8-acetyl-7-hydroxy-4-methylcoumarin (HL2) have been obtained by the electrochemical method. The density functional theory calculations and X-ray absorption spectroscopy techniques have been used to geometrically describe a series of new compounds. The studies have been focused on the coordination mode of the hydroxy ligands to the metallic centre. The complexes, Cu(HL1)2 and Cu(HL2)2⋅0.5H2O, have flat square geometry with oxygen atoms in the first coordination sphere. Two bidentate anionic coumarins are bonded to the metal cation via the acetyl and deprotonated hydroxyl O atoms. Biological activity, including microbiological and cytotoxic, has been evaluated and found to be enhanced in comparison with the parent ligands. Moreover, the Cu(II) complex with 8-acetyl-7-hydroxy-4-methylcoumarin shows similar antifungal activity as commercially used fluconazole.
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      PubDate: 2015-04-16T08:58:51Z
       
  • DNA damage and induction of apoptosis in pancreatic cancer cells by a new
           dinuclear bis(triazacyclonane) copper complex
    • Abstract: Publication date: April 2015
      Source:Journal of Inorganic Biochemistry, Volume 145
      Author(s): Diego Montagner , Valentina Gandin , Cristina Marzano , Andrea Erxleben
      The dinuclear copper(II) complex [Cu2{bcmp(-H)}(μ-OH)](NO3)2·H2O (1, bcmp=2,6-bis(1,4,7-triazacyclonon-1-ylmethyl)-4-methylphenol) has been synthesized and characterized by electrospray ionization mass spectrometry, potentiometric titration and cyclovoltammetry. The X-ray structure of the analogous perchlorate salt [Cu2{bcmp(-H)}(μ-OH)](ClO4)2·2.5H2O (2) was determined. Cytotoxicity studies showed very promising activity of 1 against various pancreatic tumor cell lines with IC50 values comparable or even lower than those of cisplatin. The Cu complex displayed low toxicity against a human non-tumor cell line (HEK 293) demonstrating selectivity for cancer cells. 1 converts supercoiled pUC19 plasmid DNA into the nicked form at micromolar concentrations in the absence of added reductants. A detailed kinetic study on the hydrolysis of the DNA model bis(2,4-dinitrophenyl) phosphate (BDNPP) has been performed. 1 hydrolyses BDNPP with a second order rate constant of 0.047Ms−1 at pH8 and 40°C. Finally, single cell electrophoresis (comet assay) and fluorescence microscopy analysis showed that 1 interacts with cellular DNA and induces apoptotic cell death of Capan-1 pancreatic cancer cells. Western blotting analysis indicated that the Cu complex activates the p53 dependent pathway of apoptosis.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Heteroditopic P,N ligands in gold(I) complexes: Synthesis, structure and
           cytotoxicity
    • Abstract: Publication date: April 2015
      Source:Journal of Inorganic Biochemistry, Volume 145
      Author(s): Telisha Traut-Johnstone , Stonard Kanyanda , Frederik H. Kriel , Tanya Viljoen , P.D. Riekert Kotze , Werner E. van Zyl , Judy Coates , D. Jasper G. Rees , Mervin Meyer , Raymond Hewer , D. Bradley G. Williams
      New heteroditopic, bi- and multidentate imino- and aminophosphine ligands were synthesised and complexed to [AuCl(THT)] (THT=tetrahydrothiophene). X-ray crystallography confirmed Schiff base formation in three products, the successful reduction of the imino-group to the sp3-hybridised amine in several instances, and confirmed the formation of mono-gold(I) imino- and aminophosphine complexes for four Au-complexes. Cytotoxicity studies in cancerous and non-cancerous cell lines showed a marked increase in cytotoxicity upon ligand complexation to gold(I). These findings were supported by results from the 60-cell line fingerprint screen of the Developmental Therapeutics Programme of the National Institutes of Health for two promising compounds. The cytotoxicity of some of these ligands and gold(I)complexes is due to the induction of apoptosis. The ligands and gold(I)complexes demonstrated selective toxicity towards specific cell lines, with Jurkat T cells being more sensitive to the cytotoxic effects of these compounds, while the non-cancerous human cell line KMST6 proved more resistant when compared to the cancerous cell lines. Results from the NIH DTP 60 cell-line fingerprint screen support the observed enhancement of cytotoxicity upon gold(I) complexation. One gold(I)complex induced high levels of apoptosis at concentrations of 50μM in all the cell lines screened in this study, while some of the other compounds selectively induced apoptosis in the cell lines. These results point towards the potential for selective toxicity to cancerous cells through the induction of apoptosis.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Eu(III) luminescence and tryptophan fluorescence spectroscopy as a tool
           for understanding interactions between hen egg white lysozyme and
           metal-substituted Keggin type polyoxometalates
    • Abstract: Publication date: Available online 1 April 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Vincent Goovaerts , Karen Stroobants , Gregory Absillis , Tatjana N. Parac-Vogt
      The interaction between the lacunary Keggin K7PW11O39, the Eu(III)-substituted Keggin K4EuPW11O39 (Eu-Keggin) and the Ce(IV)-substituted Keggin [Me2NH2]10[Ce(PW11O39)2] (Ce-Keggin) polyoxometalates (POMs), and the proteins hen egg white lysozyme (HEWL) and the structurally homologous α-lactalbumin (α-LA) was studied by steady state and time-resolved Eu(III) luminescence and tryptophan (Trp) fluorescence spectroscopy. The excitation spectrum of Eu-Keggin at lower concentrations ([Eu-Keggin]<100μM) is dominated by a ligand-to-metal charge transfer band (291nm). For higher concentrations ([Eu-Keggin]>250μM) the 5L6 ← 7F0 transition becomes the most intense peak. In the absence of protein, the number of coordinated water molecules to the Eu(III) centre of Eu-Keggin is 4, indicating a 1:1 Eu(III):POM species. In the presence of phosphate buffer this number linearly decreases from 4 to 2 upon increasing phosphate buffer concentration. Upon addition of HEWL, there are no coordinated water molecules, suggesting interaction between Eu-Keggin and the protein surface. In addition, this interaction results in a more than threefold increase of the hypersensitive 5D0 → 7F2 transition for the Eu-Keggin/HEWL mixture. The calculated association constant amounted to 2.2×102 M−1 for the Eu-Keggin/HEWL complex. Tryptophan fluorescence quenching studies were performed and the quenching constants were calculated to be 9.1×104 M−1, 4×104 M−1 and 4.1×105 M−1 for the lacunary Keggin/HEWL, the Eu-Keggin/HEWL and the Ce-Keggin/HEWL complexes, respectively. The number of bound POM molecules to HEWL was 1.04 for the lacunary Keggin POM, and 1.0 for Eu-Keggin, indicating the formation of a 1:1 POM/HEWL complex. The value of 1.38 for Ce-Keggin might indicate a transition from 1:1 to 1:2 interaction.
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      PubDate: 2015-04-16T08:58:51Z
       
  • HSA-based phosphorescent probe for two-photon in vitro visualization
    • Abstract: Publication date: Available online 1 April 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Pavel S. Chelushkin , Natalia V. Nukolova , Alexei S. Melnikov , Pavel Yu. Serdobintsev , Pavel A. Melnikov , Dmitry V. Krupenya , Igor O. Koshevoy , Sergey V. Burov , Sergey P. Tunik
      Two-photon microscopy reveals several advantages over conventional one since it provides higher spatial resolution as well as deeper penetration into the sample under study. The development of suitable two-photon probes is one of the most challenging tasks in this area. Here we present phosphorescent non-covalent adduct of human serum albumin and Au-Ag alkynyl-diphosphine complex, [Au14Ag4(C2Ph)12(PPh2C6H4PPh2)6][PF6]4, which exhibits high cross section of two-photon-induced luminescence (δ TPE) within large near-infrared excitation wavelength region (700–800nm) with maximum δ TPE about 38 GM at 740nm. This feature makes it a promising probe for multiphoton bioimaging as demonstrated by successful visualization of glioma C6 cells and various tissues by two-photon confocal microscopy both in planar and z-stacking modes. Additionally, the broad excitation region enables optimization of the signal-to-background auto-fluorescence ratio via variation of excitation wavelength.
      Graphical abstract image

      PubDate: 2015-04-16T08:58:51Z
       
  • Reactions of model proteins with aurothiomalate, a clinically established
           gold(I) drug: The comparison with auranofin
    • Abstract: Publication date: Available online 1 April 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Farivash Darabi , Tiziano Marzo , Lara Massai , Federica Scaletti , Elena Michelucci , Luigi Messori
      Aurothiomalate (AuTm) is an old, clinically established, antiarthritic gold drug that is currently being reconsidered as a candidate drug for cancer treatment and for other therapeutic indications within a more general drug repositioning program. As the biological effects of gold drugs seem to be mediated, mainly, by their interactions with protein targets we have analyzed here, in detail, the metalation patterns produced by aurothiomalate in a few model proteins. In particular, the reactions of aurothiomalate with the small proteins ribonuclease A, cytochrome c and lysozyme were explored through ESI MS (electrospray ionization mass spectrometry) analysis. Notably, characteristic and rather constant features emerged in the protein metalation patterns induced by AuTm that are markedly distinct from those caused by auranofin; a non-covalent interaction mode is invoked for AuTm binding to the mentioned proteins. The affinity constants of AuTm toward the three mentioned proteins were also initially assessed. The implications of the present findings are discussed.
      Graphical abstract image

      PubDate: 2015-04-16T08:58:51Z
       
  • Cis-[RuCl(BzCN)(N–N)(P–P)]PF6 complexes: Synthesis and in
           vitro antitumor activity (BzCN=benzonitrile;
           N–N=2,2′-bipyridine; 1,10-phenanthroline;
           P–P=1,4-bis(diphenylphosphino) butane,
           1,2-bis(diphenylphosphino)ethane, or
           1,1′-(diphenylphosphino)ferrocene)
    • Abstract: Publication date: Available online 31 March 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Flávia de C. Pereira , Benedicto A.V. Lima , Aliny P. de Lima , Wanessa C. Pires , Thallita Monteiro , Lorena F. Magalhães , Wanderson Costa , Angélica E. Graminha , Alzir A. Batista , Javier Ellena , Elisângela de P. Siveira-Lacerda
      The motivation to use ruthenium complexes in cancer treatment has led our research group to synthesize complexes with this metal and test them against several types of tumor cells, yielding promising results. In this paper the results of biological tests, assessed by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, were carried out on the complexes cis-[RuCl(BzCN)(bipy)(dppe)]PF6 (1), cis-[RuCl(BzCN)(bipy)(dppb)]PF6 (2), cis-[RuCl(BzCN)(bipy)(dppf)]PF6 (3) and cis-[RuCl(BzCN)(phen)(dppb)]PF6 (4) which are described [BzCN=benzonitrile; bipy=2,2′-bipyridine; phen=1,10-phenanthroline; dppe=1,2-bis(diphenylphosphino) ethane; dppb=1,4-bis-(diphenylphosphino)butane; dppf=1,1′-bis(diphenylphosphino)ferrocene]. The present study is focused on the cytotoxic activity of complexes (1)–(4) against four tumor cell lines and on the apoptosis and changes in the cell cycle and gene expression observed in the sarcoma 180 (S180) tumor cell line treated with complex (1). The results demonstrated that this complex inhibits S180 cell growth, with an IC50 of 17.02±8.21μM, while exhibiting lower cytotoxicity (IC50 =53.73±5.71μM) towards lymphocytes (normal cells). Flow cytometry revealed that the complex inhibits the growth of tumor cells by inducing apoptosis as evidenced by an increase in the proportion of cells positive for annexin V staining and G0/G1 phase cell-cycle arrest. Further investigation showed that complex (1) induces a drop in the mitochondrial membrane potential and provokes a decrease in Bcl-2 protein expression and increase in caspase 3 activation, while the increased activation of caspase 8 caused a decrease in the gene expression in caspases 3 and 9. Increases in Tp53 and Bax expressions were also observed.
      Graphical abstract image

      PubDate: 2015-04-16T08:58:51Z
       
  • Metals in the active site of native protein phosphatase-1
    • Abstract: Publication date: Available online 30 March 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Ewald Heroes , Jens Rip , Monique Beullens , Luc Van Meervelt , Stefan De Gendt , Mathieu Bollen
      Protein phosphatase-1 (PP1) is a major protein Ser/Thr phosphatase in eukaryotic cells. Its activity depends on two metal ions in the catalytic site, which were identified as manganese in the bacterially expressed phosphatase. However, the identity of the metal ions in native PP1 is unknown. In this study, total reflection X-ray fluorescence (TXRF) was used to detect iron and zinc in PP1 that was purified from rabbit skeletal muscle. Metal exchange experiments confirmed that the distinct substrate specificity of recombinant and native PP1 is determined by the nature of their associated metals. We also found that the iron level associated with native PP1 is decreased by incubation with inhibitor-2, consistent with a function of inhibitor-2 as a PP1 chaperone.
      Graphical abstract image

      PubDate: 2015-04-16T08:58:51Z
       
  • Caged oligonucleotides for studying biological systems
    • Abstract: Publication date: Available online 28 March 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Brittani K. Ruble , Sean B. Yeldell , Ivan J. Dmochowski
      Light-activated (“caged”) compounds have been widely employed for studying biological processes with high spatial and temporal control. In the past decade, several new approaches for caging the structure and function of DNA and RNA oligonucleotides have been developed. This review focuses on caged oligonucleotides that incorporate site-specifically one or two photocleavable linkers, whose photolysis yields oligonucleotides with dramatic structural and functional changes. This technique has been employed by our laboratory and others to photoregulate gene expression in cells and living organisms, typically using near UV-activated organic chromophores. To improve capabilities for in vivo studies, we harnessed the rich inorganic photochemistry of ruthenium bipyridyl complexes to synthesize Ru-caged morpholino antisense oligonucleotides that remain inactive in zebrafish embryos until uncaged with visible light. Expanding into new caged oligonucleotide applications, our lab has developed Transcriptome In Vivo Analysis (TIVA) technology, which provides the first noninvasive, unbiased method for isolating mRNA from single neurons in brain tissues. TIVA-isolated mRNA can be amplified and then analyzed using next-generation sequencing (RNA-seq).
      Graphical abstract image

      PubDate: 2015-04-16T08:58:51Z
       
  • Corrigendum to “Cyclopalladated and cycloplatinated benzophenone
           imines: Antitumor, antibacterial and antioxidant activities, DNA
           interaction and cathepsin B inhibition” [J. Inorg. Biochem. 140
           (2014) 80–88]
    • Abstract: Publication date: Available online 27 March 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Joan Albert , Lucía D'Andrea , Jaume Granell , Pepita Pla-Vilanova , Josefina Quirante , Muhammad Kaleem Khosa , Carme Calvis , Ramon Messeguer , Josefa Badía , Laura Baldomà , Mercè Font-Bardia , Teresa Calvet



      PubDate: 2015-04-16T08:58:51Z
       
  • Design, Synthesis and Characterization of Novel Binary V(V)-Schiff Base
           Materials Linked with Insulin-Mimetic Vanadium-Induced Differentiation of
           3T3-L1 Fibroblasts to Adipocytes. Structure-Function Correlations at the
           Molecular Level
    • Abstract: Publication date: Available online 26 March 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): E. Halevas , O. Tsave , M.P. Yavropoulou , A. Hatzidimitriou , J.G. Yovos , V. Psycharis , C. Gabriel , A. Salifoglou
      Among the various roles of vanadium in the regulation of intracellular signaling, energy metabolism and insulin mimesis, its exogenous activity stands as a contemporary challenge currently under investigation and a goal to pursue as a metallodrug against Diabetes mellitus II. In this regard, the lipogenic activity of vanadium linked to the development of well-defined antidiabetic vanadodrugs has been investigated through: a) specifically designing and synthesizing Schiff-base organic ligands L, bearing a variable number of terminal alcohols, b) a series of well-defined soluble binary V(V)-L compounds synthesized and physicochemically characterized, c) a study of their cytotoxic effect and establishment of adipogenic activity in 3T3-L1 fibroblasts toward mature adipocytes, and d) biomarker examination of a closely-linked molecular target involving or influenced by the specific V(V) forms, cumulatively delineating factors involved in potential pathways linked to V(V)-induced insulin-like activity. Collectively, the results a) project the importance of specific structural features in Schiff-ligands bound to V(V), thereby influencing the emergence of its (a)toxicity and for the first time its insulin-like activity in pre-adipocyte differentiation, b) contribute to the discovery of molecular targets influenced by the specific vanadoforms seeking to induce glucose uptake, and c) indicate an interplay of V(V) structural speciation and cell-differentiation biological activity, thereby gaining insight into vanadium’s potential as a future metallodrug in Diabetes mellitus.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Iron diminishes the in vitro biological effect of vanadium
    • Abstract: Publication date: Available online 25 March 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Andrew J. Ghio , Jacqueline Stonehuerner , Joleen M. Soukup , Lisa A. Dailey , Matthew J. Kesic , Mitchell D. Cohen
      Mechanistic pathways underlying inflammatory injury following exposures to vanadium-containing compounds are not defined. We tested the postulate that the in vitro biological effect of vanadium results from its impact on iron homeostasis. Human bronchial epithelial (HBE) cells exposed to vanadyl sulfate (VOSO4) showed a time- and dose-dependent increase in vanadium relative to PBS. HBE cells exposed to VOSO4 and then exposed to ferric ammonium citrate (FAC) significantly increased intracellular iron import supporting an interaction between the two metals. Following exposure to VOSO4, there was an increase (336±73%) in RNA for divalent metal transporter 1 (DMT1), a major iron importer. With inclusion of VOSO4 in the incubation, vanadium could be measured in the nuclear and mitochondrial fractions and the supernatant. Non-heme iron in the nuclear and mitochondrial fractions were decreased immediately following VOSO4 exposure while there was an increased concentration of non-heme iron in the supernatant. Provision of excess iron inhibited changes in the concentration of this metal provoked by VOSO4 exposures. Using Amplex Red, VOSO4 was shown to significantly increase oxidant generation by HBE cells in a time- and dose-dependent manner. HBE cells pre-treated with FAC and then exposed to VOSO4 demonstrated a decreased generation of oxidants. Similarly, activation of the transcription factor NF-ĸB promoter and release of interleukin-6 and -8 were increased following VOSO4 exposure and these effects were diminished by pre-treatment with FAC. We conclude that an initiating event in biological effect after exposure to vanadyl sulfate is a loss of requisite cell iron.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Thirty years through vanadium chemistry
    • Abstract: Publication date: Available online 24 March 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): J. Costa Pessoa
      The relevance of vanadium in biological systems is known for many years and vanadium-based catalysts have important industrial applications, however, till the beginning of the 80s research on vanadium chemistry and biochemistry did not receive much attention from the scientific community. The understanding of the broad bioinorganic implications resulting from the similarities between phosphate and vanadate(V) and the discovery of vanadium dependent enzymes gave rise to an enormous increase in interest in the chemistry and biological relevance of vanadium. Thereupon the last 30years corresponded to a period of enormous research effort in these fields, as well as in medicinal applications of vanadium and in the development of catalysts for use in fine-chemical synthesis, some of these inspired by enzymatic active sites. Since the 80s my group in collaboration with others made contributions, described throughout this text, namely in the understanding of the speciation of vanadium compounds in aqueous solution and in biological fluids, and to the transport of vanadium compounds in blood plasma and their uptake by cells. Several new types of vanadium compounds were also synthesized and characterized, with applications either as prospective therapeutic drugs or as homogeneous or heterogenized catalysts for the production of fine chemicals. The developments made are described also considering the international context of the evolution of the knowledge in the chemistry and bioinorganic chemistry of vanadium compounds during the last 30years. This article was compiled based on the Vanadis Award presentation at the 9th International Vanadium Symposium.
      Graphical abstract image

      PubDate: 2015-04-16T08:58:51Z
       
  • A novel resting form of the trinuclear copper center in the double mutant
           of a multicopper oxidase, CueO, Cys500Ser/Glu506Ala
    • Abstract: Publication date: Available online 24 March 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Takao Kajikawa , Ryosuke Sugiyama , Kunishige Kataoka , Takeshi Sakurai
      A multicopper oxidase, CueO was doubly mutated at its type I copper ligand, Cys500 and an acidic amino acid residue located in the proton transfer pathway, Glu506, to Ser and Ala, respectively. Cys500Ser/Glu506Ala was mainly in a novel resting form to afford the absorption band at ca. 400nm and an EPR signal with a highly anisotropic character derived from type III copper. However, Cys500Ser/Glu506Ala gave the same reaction intermediate (peroxide intermediate) as that from Cys500Ser and Cys500Ser/Glu506Gln.
      Graphical abstract image

      PubDate: 2015-04-16T08:58:51Z
       
  • Lights and shadows in the challenge of binding acyclovir, a synthetic
           purine-like nucleoside with antiviral activity, at an apical–distal
           coordination site in copper(II)-polyamine chelates
    • Abstract: Publication date: Available online 23 March 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Inmaculada Pérez-Toro , Alicia Domínguez-Martín , Duane Choquesillo-Lazarte , Esther Vílchez-Rodríguez , Josefa María González-Pérez , Alfonso Castiñeiras , Juan Niclós-Gutiérrez
      Several nucleic acid components and their metal complexes are known to be involved in crucial metabolic steps. Therefore the study of metal–nucleic acid interactions becomes essential to understand these biological processes. In this work, the synthetic purine-like nucleoside acyclovir (acv) has been used as a model of guanosine recognition with copper(II)-polyamine chelates. The chemical stability of the N9-acyclic arm in acv offers the possibility to use this antiviral drug to deepen the knowledge of metal–nucleoside interactions. Cu(II) chelates with cyclam, cyclen and trien were used as suitable receptors. All these copper(II) tetraamine chelates have in common the potential ability to yield a Cu–N7(apical) bond assisted by an appropriate (amine)N–H⋯O6(acv) intra-molecular interligand interaction. A series of synthesis afforded the following compounds: [Cu(cyclam)(ClO4)2] (1), {[Cu(cyclam)(μ2-NO3)](NO3)}n (2), {[Cu(cyclam)(μ2-SO4)]·MeOH}n (3), {[Cu(cyclam)(μ2-SO4)]·5H2O}n (4), [Cu(cyclen)(H2O)]SO4·2H2O (5), [Cu(cyclen)(H2O)]SO4·3H2O (6), [Cu(trien)(acv)](NO3)2·acv (7) and [Cu(trien)(acv)]SO4·0.71H2O (8). All these compounds have been characterized by X-ray crystallography and FT-IR spectroscopy. Our results reveal that the macrochelates Cu(cyclen)2+ and Cu(cyclam)2+ are unable to bind acv at an apical site. In contrast, the Cu(trien)2+ complex has proved to be an efficient receptor for acv in compounds (7) and (8). In the ternary complex [Cu(trien)(acv)]2+, the metal binding pattern of acv consists of an apical Cu–N7 bond assisted by an intra-molecular (primary amino)N–H⋯O6(acv) interligand interaction. Structural comparisons reveal that this unprecedented apical role of acv is due to the acyclic nature of trien together with the ability of the Cu(trien)2+ chelate to generate five-coordinated (type 4+1) copper(II) complexes.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Investigation of VO–salophen complexes electronic structure
    • Abstract: Publication date: Available online 13 March 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Simone Bertini , Alessia Coletti , Barbara Floris , Valeria Conte , Pierluca Galloni
      Vanadyl N,N′-bis(salicylidene)-o-phenylenediamine (salophen) complexes have been extensively investigated by cyclic voltammetry, UV–visible spectroscopy and theoretical calculations in MeCN, THF (tetrahydrofuran) and DMF (N,N-dimethylformamide), in order to elucidate the overall factors that influence the electronic density of the metal and therefore the properties of these complexes in various applications. Different substituents were introduced into the salophen skeleton to change the vanadium electron density. Results obtained and here presented showed that the substituents influence the metal electronic character in a way that cannot be easily predicted by considering only the electronic effect. Similarly, the solvent polarity or coordination ability affects the metal complex properties in an unpredictable way. Therefore, experimental and theoretical data here collected are a powerful tool to a priori design salophen ligands to obtain vanadyl complexes having the specific electronic properties suitable for desired applications.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Expanding the family of heteroleptic oxidovanadium(IV) compounds with
           salicylaldehyde semicarbazones and polypyridyl ligands showing
           anti-Trypanosoma cruzi activity
    • Abstract: Publication date: Available online 12 March 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Gonzalo Scalese , Julio Benítez , Santiago Rostán , Isabel Correia , Lara Bradford , Marisol Vieites , Lucía Minini , Alicia Merlino , E. Laura Coitiño , Estefania Birriel , Javier Varela , Hugo Cerecetto , Mercedes González , João Costa Pessoa , Dinorah Gambino
      Searching for prospective vanadium-based drugs for the treatment of Chagas disease, a new series of heteroleptic [VIVO(L-2H)(NN)] compounds was developed by including the lipophilic 3,4,7,8-tetramethyl-1,10-phenanthroline (tmp) NN ligand and seven tridentate salicylaldehyde semicarbazone derivatives (L1–L7). The compounds were characterized in the solid state and in solution. EPR spectroscopy suggests that the NN ligand is bidentate bound through both nitrogen donor atoms in an axial–equatorial mode. The EPR and 51V-NMR spectra of aerated solutions at room temperature indicate that the compounds are stable to hydrolysis and that no significant oxidation of VIV to VV takes place at least in 24h. The complexes are more active in vitro against Trypanosoma cruzi, the parasite responsible for Chagas disease, than the reference drug Nifurtimox and most of them are more active than previously reported [VIVO(L-2H)(NN)] complexes of other NN co-ligands. Selectivity towards the parasite was analyzed using J-774 murine macrophages as mammalian cell model. Due to both, high activity and high selectivity, L2, L4, L5 and L7 complexes could be considered new hits for further drug development. Lipophilicity probably plays a relevant role in the bioactivity of the new compounds. The [VIVO(L-2H)(NN)] compounds were designed aiming DNA as potential molecular target. Therefore, the novel L1–L7 tmp complexes were screened by computational modeling, comparing their DNA-binding features with those of previously reported [VIVO(L-2H)(NN)] compounds with different NN co-ligands. Whereas all the complexes interact well with DNA, with binding modes and strength tuned in different extents by the NN and semicarbazone co-ligands, molecular docking suggests that the observed anti-T. cruzi activity cannot be explained upon DNA intercalation as the sole mechanism of action.
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      PubDate: 2015-04-16T08:58:51Z
       
  • Properties of the indole ring in metal complexes. A comparison with the
           phenol ring
    • Abstract: Publication date: Available online 11 March 2015
      Source:Journal of Inorganic Biochemistry
      Author(s): Yuichi Shimazaki , Tatsuo Yajima , Osamu Yamauchi
      Tryptophan (Trp), an essential amino acid, has an indole ring with a high electron density and is frequently seen at the proximal position of the metal site in metalloproteins. For example, the indole ring of Trp has been reported to interact weakly with Cu(I) in a Cu chaperone CusF. Another aromatic amino acid, tyrosine (Tyr), has a phenol ring, which is an important metal binding site in various metalloproteins. Although the structures of the aromatic rings are different, they both have a weakly acidic moiety and perform some similar roles in biological systems, such as radical formation and electron transfer. In this review, we focus on these and other properties of the indole and phenol rings in metal-containing systems.
      Graphical abstract image

      PubDate: 2015-04-16T08:58:51Z
       
 
 
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