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  Subjects -> CHEMISTRY (Total: 847 journals)
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INORGANIC CHEMISTRY (42 journals)

Acta Polymerica     Hybrid Journal   (Followers: 7)
Additives for Polymers     Full-text available via subscription   (Followers: 21)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Polymer Technology     Hybrid Journal   (Followers: 13)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 3)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 7)
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: 44)
Heterocyclic Communications     Hybrid Journal   (Followers: 1)
High Performance Polymers     Hybrid Journal  
Indian Journal of Chemistry - Section A     Open Access   (Followers: 7)
Inorganic Chemistry     Full-text available via subscription   (Followers: 24)
Inorganic Chemistry Communications     Hybrid Journal   (Followers: 10)
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: 7)
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: 7)
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 3)
Journal of Inorganic Chemistry     Open Access   (Followers: 3)
Journal of Polymer Engineering     Hybrid Journal   (Followers: 9)
Journal of Polymers and the Environment     Hybrid Journal   (Followers: 3)
Journal of Separation Science     Hybrid Journal   (Followers: 11)
Metallodrugs     Open Access   (Followers: 1)
Open Journal of Inorganic Chemistry     Open Access   (Followers: 3)
Plasmas and Polymers     Hybrid Journal  
Polymer Bulletin     Hybrid Journal   (Followers: 7)
Polymer Composites     Hybrid Journal   (Followers: 14)
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  [2805 journals]
  • Editorial Board
    • Abstract: Publication date: June 2016
      Source:Journal of Inorganic Biochemistry, Volume 159




      PubDate: 2016-04-22T05:20:47Z
       
  • Contents
    • Abstract: Publication date: June 2016
      Source:Journal of Inorganic Biochemistry, Volume 159




      PubDate: 2016-04-22T05:20:47Z
       
  • Zinc complexes of flufenamic acid: Characterization and biological
           evaluation
    • Abstract: Publication date: Available online 22 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Alketa Tarushi, Philippos Kastanias, Catherine P. Raptopoulou, Vassilis Psycharis, Dimitris P. Kessissoglou, Athanasios N. Papadopoulos, George Psomas
      The reaction of ZnCl2 with the non-steroidal anti-inflammatory drug flufenamic acid (Hfluf) led to the formation of complex [Zn(fluf-O)2(MeOH)4], 1. When the reaction takes places in the presence of a N,N′-donor heterocyclic ligand 2.2′-bipyridylamine (bipyam), 2.2′-bipyridine (bipy), 1.10-phenanthroline (phen) and 2.2′-dipyridylketone oxime (Hpko), the complexes [Zn(fluf)2(bipyam)], 2, [Zn(fluf)2(bipy)], 3, [Zn(fluf)(phen)2(H2O)](fluf)·0.2MeOH, 4·0.2MeOH and [Zn(fluf)2(Hpko)2], 5 were isolated, respectively. The complexes were characterized by physicochemical and spectroscopic techniques and the crystal structures of complexes 2 and 4 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 and to inhibit soybean lipoxygenase was evaluated; the complexes were more active than free Hfluf. The interaction of the complexes with serum albumins was investigated by fluorescence emission spectroscopy and the corresponding binding constants were calculated. UV–vis spectroscopy, viscosity measurements and fluorescence emission spectroscopy for the competitive studies of the complexes with ethidium bromide were the techniques employed to monitor the interaction of the complexes with calf-thymus DNA and revealed intercalation as the most possible mode of binding.
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      PubDate: 2016-04-22T05:20:47Z
       
  • Small-volume potentiometric titrations: EPR investigations of Fe-S cluster
           N2 in mitochondrial complex I
    • Abstract: Publication date: Available online 20 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): John J. Wright, Enrico Salvadori, Hannah R. Bridges, Judy Hirst, Maxie M. Roessler
      EPR-based potentiometric titrations are a well-established method for determining the reduction potentials of cofactors in large and complex proteins with at least one EPR-active state. However, such titrations require large amounts of protein. Here, we report a new method that requires an order of magnitude less protein than previously described methods, and that provides EPR samples suitable for measurements at both X- and Q-band microwave frequencies. We demonstrate our method by determining the reduction potential of the terminal [4Fe-4S] cluster (N2) in the intramolecular electron-transfer relay in mammalian respiratory complex I. The value determined by our method, E m7 =−158mV, is precise, reproducible, and consistent with previously reported values. Our small-volume potentiometric titration method will facilitate detailed investigations of EPR-active centres in non-abundant and refractory proteins that can only be prepared in small quantities.
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      PubDate: 2016-04-22T05:20:47Z
       
  • Ruthenium(II) polypyridyl complexes with 1,8-naphthalimide group as DNA
           binder, photonuclease, and dual inhibitors of topoisomerases I and
           IIα
    • Abstract: Publication date: Available online 20 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Yanmei Sun, Jia Li, Hong Zhao, Lifeng Tan
      Two ruthenium(II) polypyridyl complexes containing 1,8-naphthalimide group as DNA binders, photonucleases, and inhibitors of topoisomerases I and IIα are evaluated. The binding properties of [Ru(phen)2(pnip)]2+ {1; phen=1,10-phenanthroline; pnip=12-[N-(p-phenyl)-1,8-napthalimide]- imidazo[4′,5′-f] [1,10]phenanthroline} and [Ru(bpy)2(pnip)]2+ (2; bpy=2,2′-bipyridine) with calf thymus DNA increases with increasing the bulkiness and hydrophobic character of ancillary ligands, although the two complexes possess high affinities for DNA via intercalation. Moreover, photoirradiation (λ=365nm) of the two complexes are found to induce strand cleavage of closed circular pBR322 plasmid DNA via singlet oxygen mechanism, while complex 1 displays more effective photocleavage activity than complex 2 under the same conditions. Topoisomerase inhibition and DNA strand passage assay reflect that complexes 1 and 2 are efficient dual poisons of topoisomerases I and IIα.
      Graphical abstract image

      PubDate: 2016-04-22T05:20:47Z
       
  • 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: Available online 20 April 2016
      Source:Journal of Inorganic Biochemistry
      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: 2016-04-22T05:20:47Z
       
  • Synthesis, structural characterization, cytotoxic properties and DNA
           binding of a dinuclear copper(II) complex
    • Abstract: Publication date: Available online 21 April 2016
      Source:Journal of Inorganic Biochemistry
      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.
      Graphical abstract image

      PubDate: 2016-04-22T05:20:47Z
       
  • Hybrid Catechin Silica Nanoparticle Influence on Cu(II) Toxicity and
           Morphological Lesions in Primary Neuronal Cells
    • Abstract: Publication date: Available online 21 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): E. Halevas, C.M. Nday, A. Salifoglou
      Morphological alterations compromising inter-neuronal connectivity may be directly linked to learning-memory deficits in Central Nervous System neurodegenerative processes. Cu(II)-mediated oxidative stress plays a pivotal role in regulating redox reactions generating reactive oxygen species (ROS) and reactive nitrogen species (RNS), known contributors to Alzheimer's disease (AD) pathology. The antioxidant properties of flavonoid catechin have been well-documented in neurodegenerative processes. However, the impact that catechin encapsulation in nanoparticles may have on neuronal survival and morphological lesions has been poorly demonstrated. To investigate potential effects of nano-encapsulated catechin on neuronal survival and morphological aberrations in primary rat hippocampal neurons, poly(ethyleneglycol) (PEG) and cetyltrimethylammoniun bromide (CTAB)-modified silica nanoparticles were synthesized. Catechin was loaded on silica nanoparticles in a concentration-dependent fashion, and release studies were carried out. Further physicochemical characterization of the new nano-materials included elemental analysis, particle size, z-potential, FT-IR, Brunauer-Emmett-Teller (BET), thermogravimetric (TGA), and scanning electron microscopy (SEM) analysis in order to optimize material composition linked to the delivery of loaded catechin in the hippocampal cellular milieu. The findings reveal that, under Cu(II)-induced oxidative stress, the loading ability of the PEGylated/CTAB silica nanoparticles was concentration-dependent, based on their catechin release profile. The overall bio-activity profile of the new hybrid nanoparticles a) denoted their enhanced protective activity against oxidative stress and hippocampal cell survival compared to previously reported quercetin, b) revealed that morphological lesions affecting neuronal integrity can be counterbalanced at high copper concentrations, and c) warrants in-depth perusal of molecular events underlying neuronal function and degeneration, collectively linked to preventive nanotechnology in neurodegeneration.
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      PubDate: 2016-04-22T05:20:47Z
       
  • Behavior of the potential antitumor VIVO complexes formed by flavonoid
           ligands. 3. Antioxidant properties and radical production capability
    • Abstract: Publication date: Available online 20 April 2016
      Source:Journal of Inorganic Biochemistry
      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) 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.
      Graphical abstract image

      PubDate: 2016-04-22T05:20:47Z
       
  • Multifunctional quinoline-triazole derivatives as potential modulators of
           amyloid-β peptide aggregation
    • Abstract: Publication date: Available online 16 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Michael R. Jones, Christine Dyrager, Marie Hoarau, Kyle J. Korshavn, Mi Hee Lim, Ayyalusamy Ramamoorthy, Tim Storr

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      PubDate: 2016-04-18T05:15:13Z
       
  • Effects of mutations in active site heme ligands on the spectroscopic and
           catalytic properties of SoxAX cytochromes
    • Abstract: Publication date: Available online 15 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): James R. Kilmartin, Paul V. Bernhardt, Rabeb Dhouib, Graeme R. Hanson, Mark J. Riley, Ulrike Kappler
      By attaching a sulfur substrate to a conserved cysteine of the SoxYZ carrier protein SoxAX cytochromes initiate the reaction cycle of the Sox (sulfur oxidation) multienzyme complex, which is the major pathway for microbial reoxidation of sulfur compounds in the environment. Despite their important role in this process, the reaction mechanism of the SoxAX cytochromes has not been fully elucidated. Here we report the effects of several active site mutations on the spectroscopic and enzymatic properties of the type II SoxAX protein from Starkeya novella, which in addition to two heme groups also contained a Cu redox centre. All substituted proteins contained these redox centres except for His231Ala which was unable to bind Cu(II). Substitution of the SoxA active site heme cysteine ligand with histidine resulted in increased microheterogeneity around the SoxA heme as determined by CW-EPR, while a SnSoxAXC236A substituted protein revealed a completely new, nitrogenous SoxA heme ligand. The same novel ligand was present in SnSoxAXH231A CW-EPR spectra, the first time that a ligand switch of the SoxA heme involving a nearby amino acid has been demonstrated. Kinetically, SnSoxAXC236A and SnSoxAXC236H showed reduced turnover, and in assays containing SoxYZ these mutants retained only ~25% of the wildtype activity. Together, these data indicate that the Cu redox centre can mediate a low level of activity, and that a possible ligand switch can occur during catalysis. It also appears that the SoxA heme cysteine ligand (and possibly the low redox potential) is important for an efficient reaction with SnSoxYZ/thiosulfate.
      Graphical abstract image

      PubDate: 2016-04-18T05:15:13Z
       
  • Oxidative stress protection by manganese complexes of tail-tied
           aza-scorpiand ligands
    • Abstract: Publication date: Available online 16 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Jorge González-García, Àlvar Martínez-Camarena, Begoña Verdejo, M. Paz Clares, Concepción Soriano, Enrique García-España, Hermás R. Jiménez, Antonio Doménech-Carbó, Roberto Tejero, Enrique Calvo, Laura Briansó-Llort, Carolina Serena, Sandra Trefler, Antonio Garcia-España
      The Mn2+ coordination chemistry of double scorpiand ligands in which two polyazacyclophane macrocycles have been connected by pyridine, phenanthroline and bipyridine spacers has been studied by potentiometry, paramagnetic NMR and electrochemistry. All ligands show high stability with Mn2+ and the complexes were formed in a wide pH range. DFT calculations support the structures and coordination geometries derived from the study. A remarkable antioxidant activity was evidenced for these systems by the McCord-Fridovich assay and in Escherichia coli sodAsodB deficient bacterial cells. The three systems were tested as anti-inflammatory drugs in human macrophages measuring the accumulation of cytokines upon lipopolysaccharide (LPS) pro-inflammatory effect. All complexes showed anti-inflammatory effect, being [Mn2 L1]4+ the most efficient one.
      Graphical abstract image

      PubDate: 2016-04-18T05:15:13Z
       
  • Synthesis of novel Iron(III) chelators based on triaza macrocycle backbone
           and 1-hydroxy-2(1H)-pyridin-2-one coordinating groups and their evaluation
           as antimicrobial agents
    • Abstract: Publication date: Available online 16 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): David G. Workman, Michael Hunter, Lynn G. Dover, David Tétard
      Several novel chelators based on 1-hydroxy-2(1H)-pyridinone coordinating groups decorating a triaza macrocyclic backbone scaffold were synthesised as potential powerful Fe3+ chelators capable of competing with bacterial siderophores. In particular, a novel chloromethyl derivative of 1-hydroxy-2(1H)-pyridinone exploiting a novel protective group for this family of coordinating groups was developed. These are the first examples of hexadentate chelators based on 1-hydroxy-2(1H)-pyridinone to be shown to have a biostatic activity against a range of pathogenic bacteria. Their efficacy as biostatic agents was assessed revealing that minor variations in the structure of the chelator can affect efficacy profoundly. The minimal inhibitory concentrations of our best tested novel chelators approach or are comparable to those for 1,4,7-tris(3-hydroxy-6-methyl-2-pyridylmethyl)-1,4,7-triazacyclononane, the best Fe3+ chelator known to date. The retarding effect these chelators have on microbial growth suggests that they could have a potential application as a co-active alongside antibiotics in the fight against infections.
      Graphical abstract image

      PubDate: 2016-04-18T05:15:13Z
       
  • Divergent assembly mechanisms of the manganese/iron cofactors in R2lox and
           R2c proteins
    • Abstract: Publication date: Available online 16 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Yuri Kutin, Vivek Srinivas, Matthieu Fritz, Ramona Kositzki, Hannah S. Shafaat, James Birrell, Eckhard Bill, Michael Haumann, Wolfgang Lubitz, Martin Högbom, Julia J. Griese, Nicholas Cox
      The Mn/Fe cofactor found in two classes of ferritin-like proteins, the small subunit (R2) of class Ic ribonucleotide reductase (R2c) and the R2-like ligand-binding oxidase (R2lox), performs multi-electron oxidative chemistry. It is unclear how a heterodimeric Mn/Fe metallocofactor is assembled in these two related proteins as opposed to a homodimeric Fe/Fe cofactor, especially considering the structural similarity and proximity of the two metal-binding sites in both protein scaffolds and the similar first coordination sphere ligand preferences of MnII and FeII. Using EPR and Mössbauer spectroscopies as well as X-ray anomalous dispersion, we examined metal loading and cofactor activation of both proteins in vitro (in solution). We find divergent cofactor assembly mechanisms for the two systems. In both cases, excess MnII promotes heterobimetallic cofactor assembly. In the absence of FeII, R2c cooperatively binds MnII at both metal sites, whereas R2lox does not readily bind MnII at either site. Heterometallic cofactor assembly is favored at sub-stoichiometric FeII concentrations in R2lox. FeII and MnII likely bind to the protein in a stepwise fashion, with FeII binding to site 2 initiating cofactor assembly. In R2c, however, heterometallic assembly is presumably achieved by the displacement of MnII by FeII at site 2. The divergent metal loading mechanisms are correlated with the putative in vivo function of R2c and R2lox, and most likely with the intracellular MnII/FeII concentrations in the host organisms from which they were isolated.
      Graphical abstract image

      PubDate: 2016-04-18T05:15:13Z
       
  • Osmocenyl-tamoxifen derivatives target the thioredoxin system leading to a
           redox imbalance in Jurkat cells
    • Abstract: Publication date: Available online 13 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Valeria Scalcon, Siden Top, Hui Zhi Shirley Lee, Anna Citta, Alessandra Folda, Alberto Bindoli, Weng Kee Leong, Michèle Salmain, Anne Vessières, Gérard Jaouen, Maria Pia Rigobello
      The synthesis and the biological effects of two ferrocifen analogs in the osmium series, namely the monophenolic complex 1, the tamoxifen-like complex 2 and their oxidized quinone methide (QM) derivatives, 1-QM and 2-QM, are reported. Inhibition of purified thioredoxin reductase (TrxR) is observed with 1 and 2 only after their enzymatic oxidation by the hydrogen peroxide/horseradish peroxidase (H2O2/HRP) system with IC50 of 2.4 and 1.2μM respectively. However, this inhibition is larger than that obtained with the corresponding quinone methides (IC50 =5.4μM for 1-QM and 3.6μM for 2-QM). The UV–Vis spectra of 1 or 2 incubated in the presence of H2O2/HRP show that the species generated is not a quinone methide, but probably the corresponding cation. In Jurkat cells, 2 shows high toxicity (IC50 =7.4μM), while 1 is less effective (IC50 =42μM). Interestingly, a significant inhibition of TrxR activity is observed in cells incubated with 2 (about 70% inhibition with 15μM) while the inhibition induced by 1 is much weaker (about 30% inhibition with 50μM). This strong inhibition of TrxR by 2 leads to accumulation of thioredoxin and peroxiredoxin 3 in oxidized form and to a decrease of the mitochondrial membrane potential (MMP). These results show that cytotoxicity of the osmocifens depends on their oxidation within the cell and that inhibition of thioredoxin reductase by oxidized species is a key factor in rationalizing the cytotoxicity of these complexes on Jurkat cells.
      Graphical abstract image

      PubDate: 2016-04-18T05:15:13Z
       
  • Dual role of LRRC8A-containing transporters on cisplatin resistance in
           human ovarian cancer cells
    • Abstract: Publication date: Available online 13 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Belinda Halling Sørensen, Celina Støving Dam, Stefan Stürup, Ian Henry Lambert
      Acquired resistance to chemotherapeutic drugs in cancer cells can reflect an ability to limit cellular drug availability, to repair drug induced DNA damage, and to limit initiation/progression of cell death (apoptosis). The leucine-rich-repeat-containing 8A (LRRC8A) protein is an essential component of volume sensitive channels for organic osmolytes (VSOAC) and volume regulated anion channels (VRAC), which are activated during the apoptotic process. Here we illustrate that cisplatin resistance in human ovarian cancer cells (A2780) correlates with a reduced expression of LRRC8A and copper transporter receptor 1 (CTR1), as well as a concomitant increased expression of copper-transporting P-type ATPases (ATP7A/ATP7B). We also find that cisplatin (Pt) accumulation correlates with LRRC8A protein expression and channel activity, i.e., the cellular Pt content is high when VSOAC is activated by depolarization of the plasma membrane or hypoosmotic cell swelling, and reduced when channel activity/LRRC8A expression is reduced by genetically silencing/pharmacological inhibition, or the cells have acquired a resistant phenotype with low LRRC8A protein expression. It is suggested that reduced LRRC8A expression in cisplatin-resistant A2780 cells ensures cell survival through limitation in cisplatin accumulation and a concomitant reduction in osmolytes loss via VSOAC/VRAC and hence instigation of the apoptotic process.
      Graphical abstract image

      PubDate: 2016-04-18T05:15:13Z
       
  • Pervanadate Induces Mammalian Ste20 Kinase 3 (MST3) Tyrosine
           Phosphorylation But Not Activation
    • Abstract: Publication date: Available online 13 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Wei-Chih Kan, Te-Ling Lu, Pin Ling, Te-Hsiu Lee, Chien-Yu Cho, Chi-Ying F. Huang, Wen-Yih Jenge, Yui-Ping Weng, Chun-Yen Chiang, Jin Bin Wu, Te-Jung Lu
      The yeast Ste20 (sterile) protein kinase, which is a serine/threonine kinase, responds to the stimulation of the G proteincoupled receptor (GPCR) pheromone receptor. Ste20 protein kinase serves as the critical component that links signaling from the GPCR/G proteins to the mitogen-activated protein kinase (MAPK) cascade in yeast. The yeast Ste20p functions as a MAP kinase kinase kinase kinase (MAP4K) in the pheromone response. Ste20-like kinases are structurally conserved from yeast to mammals. The mechanism by which MAP4K links GPCR to the MAPK pathway is less clearly defined in vertebrates. In addition to MAP4K, the tyrosine kinase cascade bridges G proteins and the MAPK pathway in vertebrate cells. Mammalian Ste20 Kinase 3 (MST3) has been categorized into the Ste20 family and has been reported to function in the regulation of cell polarity and migration. However, whether MST3 tyrosine phosphorylation regulates diverse signaling pathways is unknown. In this study, the tyrosine phosphatase inhibitor pervanadate was found to induce MST3 tyrosine phosphorylation in intact cells, and the activity of tyrosine-phosphorylated MST3 was measured. This tyrosine-directed phosphorylation was independent of MST3 activity. Parameters including protein conformation, Triton concentration and ionic concentration influenced the sensitivity of MST3 activity. Taken together, our data suggests that the serine/threonine kinase MST3 undergoes tyrosinedirected phosphorylation. The tyrosine-phosphorylated MST3 may create a docking site for the structurally conserved SH2/SH3 (Src Homology 2 and 3) domains within the Src oncoprotein. The unusual tyrosinephosphorylated MST3 may recruit MST3 to various signaling components.
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      PubDate: 2016-04-18T05:15:13Z
       
  • Influence of Chelation Strength and Bacterial Uptake of Gallium
           Salicylidene Acylhydrazide on Biofilm Formation and Virulence by
           Pseudomonas aeruginosa
    • Abstract: Publication date: Available online 14 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Shoghik Hakobyan, Olena Rzhepishevska, Erik Björn, Jean-François Boily, Madeleine Ramstedt
      Development of antibiotic resistance in bacteria causes major challenges for our society and has prompted a great need for new and alternative treatment methods for infection. One promising approach is to target bacterial virulence using for example salicylidene acylhydrazides (hydrazones). Hydrazones coordinate metal ions such as Fe(III) and Ga(III) through a five- membered and a six- membered chelation ring. One suggested mode of action is via restricting bacterial Fe uptake. Thus, it was hypothesized that the chelating strength of these substances could be used to predict their biological activity on bacterial cells. This was investigated by comparing Ga chelation strength of two hydrazone complexes, as well as bacterial Ga uptake, biofilm formation, and virulence, in the form of ExoS production and secretion by Pseudomonas aeruginosa. Equilibrium constants for deprotonation and Ga(III) binding of the hydrazone N’-(5-chloro-2-hydroxy-3-methylbenzylidene)- 2,4-dihydroxybenzhydrazide (ME0329), with anti-virulence effect against P. aeruginosa, were determined and compared to bacterial siderophores and the previously described Ga(III) 2-oxo-2-[N-(2,4,6-trihydroxy-benzylidene)-hydrazino]-acetamide (Ga-ME0163) and Ga-citrate complexes. In comparison with these two complexes, it was shown that the uptake of Ga(III) was higher from the Ga-ME0329 complex. The results further show that the Ga-ME0329 hydrazone complex reduces ExoS expression and secretion to a higher extent than Ga-citrate, Ga-ME0163 or the non-coordinated hydrazone. However, the effect against biofilm formation by P. aeruginosa, by the ME0329 complex, was similar to Ga-citrate and lower than what has been reported for Ga-ME0163.
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      PubDate: 2016-04-18T05:15:13Z
       
  • Cell cycle, apoptosis, cellular uptake and whole-transcriptome microarray
           gene expression analysis of HeLa cells treated with a ruthenium(II)-arene
           complex with an isoquinoline-3-carboxylic acid ligand
    • Abstract: Publication date: Available online 14 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Katarina K. Jovanović, Miljana Tanić, Ivanka Ivanović, Nevenka Gligorijević, Biljana P. Dojčinović, Siniša Radulović
      Ruthenium(II)-arene complexes are promising drug candidates for the therapy of solid tumors. In previous work, seven new compounds of the general formula [Ru(η6-p-cymene)(L1–7)Cl] were synthesized and characterized, of which the complex with L=isoquinoline-3-carboxylic acid (RuT 7 ) was two times as active on HeLa cells compared to normal cell line MRC-5, as indicated by IC50 values determined after 48h of incubation (45.4±3.0 vs. 84.2±5.7μM, respectively). In the present study, cell cycle analysis of HeLa cells treated with RuT 7 showed S phase arrest and an increase in sub-G1 population. The apoptotic potential of the title compound was confirmed with the Annexin V-FITC/PI assay together with a morphological evaluation of cells using fluorescent microscopy. Analysis of the intracellular accumulation of ruthenium showed 8.9ng Ru/106 cells after 6h of incubation. To gain further insight in the molecular mechanism of action of RuT 7 on HeLa cells, a whole-transcriptome microarray gene expression analysis was performed. Analysis of functional categories and signaling and biochemical pathways associated with the response of HeLa cells to treatment with RuT 7 showed that it leads the cells through the intrinsic (mitochondrial) apoptotic pathway, via indirect DNA damage due to the action of reactive oxygen species, and through direct DNA binding of RuT 7 . Statistical analysis for enrichment of gene sets associated with known drug-induced toxicities identified fewer associated toxicity profiles in RuT 7 -treated cells compared to cisplatin treatment. Altogether these results provide the basis for further development of RuT 7 in animal and pre-clinical studies as a potential drug candidate.
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      PubDate: 2016-04-18T05:15:13Z
       
  • High-frequency electron paramagnetic resonance of metal-containing
           porphyrin compounds using a microcantilever
    • Abstract: Publication date: Available online 16 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Eiji Ohmichi, Tsubasa Okamoto, Masaaki Mitani, Hideyuki Takahashi, Hitoshi Ohta
      In this article, we report a novel technique of high-frequency electron paramagnetic resonance (HFEPR) using a microcantilever. In this method, a sample is mounted on a cantilever, and the field-gradient force associated with EPR absorption is detected as a cantilever bending. By using a micrometer-sized cantilever, this technique can be applied to a very tiny sample on the order of μg. In addition, the use of a piezoresistive cantilever makes the experimental setup easy and compact. In this study, we applied this technique to multi-frequency HFEPR measurements of metal-containing porphyrin compounds, which are an important composing element of metal-containing proteins and coenzymes such as hemoglobin and cyanocobalamin.
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      PubDate: 2016-04-18T05:15:13Z
       
  • Deferoxamine-induced increase in the intracellular iron levels in highly
           aggressive breast cancer cells leads to increased cell migration by
           enhancing TNF-α-dependent NF-κB signaling and TGF-β
           signaling
    • Abstract: Publication date: Available online 14 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Ping Liu, Kun He, Hongjiao Song, Zhufeng Ma, Weihai Ying, Lisa X. Xu
      Recent studies have suggested that excess iron accumulation may be a risk factor for breast cancer. However the role of iron in breast cancer metastasis has remained unclear. The major goal of our study is to investigate the roles of iron in breast cancer metastasis. We modulated the intracellular iron levels of human breast cancer cells, including the aggressive MDA-MB-231 cells and non-aggressive MCF-7 cells, by using Deferoxamine (DFO) – a most widely used iron chelator. We found that DFO treatment could deplete intracellular iron in MCF-7 cells. In contrast, DFO treatment led to a significant increase in the intracellular iron level in MDA-MB-231 cells. The MDA-MB-231 cells with the increased intracellular iron level exhibited increases in both mesenchymal markers and cell migration. Furthermore, the DFO-treated MDA-MB-231 cells showed increases in both tumor necrosis factor α (TNF-α)-induced nuclear factor kappa B (NF-κB) signaling and transforming growth factor-β (TGF-β) signaling, which could contribute to the enhanced cell migration. Collectively, our study has provided the first evidence suggesting that increased intracellular iron levels could lead to enhanced migration of aggressive breast cancer cells by increasing TNF-α-dependent NF-κB signaling and TGF-β signaling. Our study has also suggested that caution should be taken when DFO is applied for treating breast cancer cells, since DFO could produce differential effects on the intracellular iron levels for aggressive breast cancer cells and non-aggressive breast cancer cells.
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      PubDate: 2016-04-18T05:15:13Z
       
  • Coordination and redox properties of copper interaction with
           α-synuclein
    • Abstract: Publication date: Available online 11 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Daniela Valensin, Simone Dell'Acqua, Henryk Kozlowski, Luigi Casella
      Parkinson's disease (PD) is a severe neurodegenerative disorder affecting movements. After Alzheimer's disease, it is the most common form of neurodegeneration. PD is characterized by the loss of neurons producing dopamine and by the presence of protein aggregates in the brain, known as Lewy bodies. The main constituent of Lewy bodies is the misfolded form of α-synuclein (αSyn), able to form oligomers and fibrils. In addition to protein aggregation, brain damage induced by oxidative stress, is also a frequent phenomenon in PD. αSyn is able to bind Copper ions in both Cu(II) and Cu(I) oxidation states. The metal binding is also maintained when αSyn interacts with membranes. Interestingly, copper binding to αSyn has strong impact either in protein misfolding or in free radical formation, such to provide a link between protein aggregation and oxidative damage. In this review the role of copper and αSyn in PD is discussed with a particular emphasis to elucidate (i) the interaction between copper and αSyn; (ii) the reactivity and (iii) potential toxicity associated with copper-αSyn complexes.
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      PubDate: 2016-04-13T15:07:33Z
       
  • Enantiomeric pair of copper(II) polypyridyl-alanine complexes: Effect of
           chirality on their interaction with biomolecules
    • Abstract: Publication date: Available online 8 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Chew Hee Ng, Cheang Wei Chan, Jing Wei Lai, Ing Hong Ooi, Kok Vei Chong, Mohd Jamil Maah, Hoi Ling Seng
      Like chiral organic drugs, the chemical and biological properties of metal complexes can be dependent on chirality. Two pairs of [Cu(phen)(ala)(H2O)]X·xH2O (phen=1.10-phenanthroline: X=NO3 −; ala: l-alanine (l-ala), 1 and d-alanine (d-ala) 2; and (X=Cl−; ala: l-ala, 3 and d-ala, 4) complex salts (x=number of lattice water molecules) have been synthesized and characterized. The crystal structure of 3 has been determined. The same pair of enantiomeric species, viz. [Cu(phen)(l-ala)(H2O)]+ and [Cu(phen)(d-ala)(H2O)]+, have been identified to be present in the aqueous solutions of both 1 and 3, and in those of both 2 and 4 respectively. Both 3 and 4 bind more strongly to ds(AT)6 than ds(CG)6. There is no or insignificant effect of the chirality of 3 and 4 on the production of hydroxyl radicals, binding to deoxyribonucleic acid from calf thymus (CT-DNA), ds(CG)6, G-quadruplex and 17-base pair duplex, and inhibition of both topoisomerase I and proteasome. Among the three proteasome proteolytic sites, the trypsin-like site is inhibited most strongly by these complexes. However, the chirality of 3 and 4 does affect the number of restriction enzymes inhibited, and their binding constants towards ds(AT)6 and serum albumin.
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      PubDate: 2016-04-09T02:21:12Z
       
  • Anthracene-Terpyridine Metal complexes as new G-Quadruplex DNA binders
    • Abstract: Publication date: Available online 9 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Sofia Gama, Inês Rodrigues, Filipa Mendes, Isabel C. Santos, Elisabetta Gabano, Beata Klejevskaja, Jorge Gonzalez-Garcia, Mauro Ravera, Ramon Vilar, António Paulo
      The formation of quadruple-stranded DNA induced by planar metal complexes has particular interest in the development of novel anticancer drugs. This is especially relevant for the inhibition of telomerase, which plays an essential role in cancer cell immortalization and is overexpressed in ca. 85-90% of cancer cells. Moreover, G-quadruplexes also exist in other locations in the human genome, namely oncogene promoter regions, and it has been hypothesized that they play a regulatory role in gene transcription. Herein we report a series of new anthracene-containing terpyridine ligands and the corresponding Cu(II) and Pt(II) complexes, with different linkers between the anthracenyl moiety and the terpyridine chelating unit. The interaction between these ligands and metal complexes with different topologies of DNA was studied by several biophysical techniques. The Pt(II) and Cu(II) complexes tested showed affinity for quadruplex-forming sequences with a good selectivity over duplex DNA. Importantly, the free ligands do not have significant affinity for any of the DNA sequences used, which shows that the presence of the metal is essential for high affinity (and selectivity). This effect is more evident in the case of the Pt(II) complexes. Moreover, the presence of a longer linker between the chelating terpyridine unit and the anthracene moiety enhances the interaction with G-quadruplex-forming sequences. We further evaluated the ability of the Cu(II) complexes to interact with, and stabilize G-quadruplex containing regions in oncogene promoters via a polymerase stop assay. These studies indicated that the metal complexes are able to induce G-quadruplex formation and stop polymerase activity.
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      PubDate: 2016-04-09T02:21:12Z
       
  • Insights into molecular mechanism of action of salan titanium(IV) complex
           with in vitro and in vivo anticancer activity
    • Abstract: Publication date: Available online 9 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Maya Miller, Ori Braitbard, Jacob Hochman, Edit Y. Tshuva
      . Titanium compounds, in particular, Ti(IV) based diaminobis(phenolato) “salan” complexes demonstrate high cytotoxicity towards a wide range of cancer cell lines in vitro, and still, very little is known on their mode of action. A representative salan Ti(IV) complex was tested both in vitro and in vivo on human HT-29 colorectal adenocarcinoma and A2780 ovarian carcinoma cells. Both cell lines were sensitive in vitro with A2780 demonstrating an enhanced rate of uptake and intracellular accumulation and thus an earlier response to the drug. HT-29 cells responded in vivo by impaired tumor development in nude mice. Both cell lines responded in vitro (but to a different extent) by upregulation of p53 with no apparent effect on p21 followed by cell cycle arrest, apoptosis and necrosis as demonstrated by sub-G1 cell accumulation and staining by Annexin-V and propidium iodide. Furthermore, time dependent activation of cysteine-aspartic proteases9 (caspase9) as well as some minor activation of cysteine-aspartic proteases3 (caspase3) support a direct effect on the apoptotic pathway. The differential response of the two cell lines to the salan titanium(IV) complex suggests that more than one pathway is involved in their growth regulation and thus could inhibit development of drug resistant variants.
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      PubDate: 2016-04-09T02:21:12Z
       
  • How half sandwich ruthenium compounds interact with DNA while not being
           hydrolyzed; a comparative study
    • Abstract: Publication date: Available online 8 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Theodoros Tsolis, Konstantinos D. Papavasileiou, Spyridon A. Divanis, Vasilios S. Melissas, Achilleas Garoufis

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      PubDate: 2016-04-09T02:21:12Z
       
  • What Computational Chemistry and Magnetic Resonance Reveal Concerning the
           Oxygen Evolving Centre in Photosystem II
    • Abstract: Publication date: Available online 8 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Richard Terrett, Simon Petrie, Rob Stranger, Ron J. Pace
      Density Functional Theory (DFT) computational studies of the Mn4/Ca Oxygen Evolving Complex (OEC) region of Photosystem II in the paramagnetic S2 and S3 states of the water oxdizing catalytic cycle are described. These build upon recent advances in computationally understanding the detailed S1 state OEC geometries, revealed by the recent high resolution Photosystem II crystal structures of Shen et al., at 1.90 Å and 1.95 Å (Petrie et al. 2015, Angew. Chem. Int. Ed., 54, 7120). The models feature a ‘Low Oxidation Paradigm’ assumption for the mean Mn oxidation states in the functional enzyme, with the mean oxidation levels being 3.0, 3.25 and 3.5 in S1, S2 and S3, respectively. These calculations are used to infer magnetic exchange interactions within the coupled OEC cluster, particularly in the Electron Paramagnetic Resonance (EPR)-visible S2 and S3 states. Detailed computational estimates of the intrinsic magnitudes and molecular orientations of the 55Mn hyperfine tensors in the S2 state are presented. These parameters, together with the resultant spin projected hyperfine values are compared with recent appropriate experimental EPR data (Continuous Wave (CW), Electron-Nuclear Double Resonance (ENDOR) and ELDOR (Electron-Electron Double Resonance)-Detected Nuclear Magnetic Resonance (EDNMR)) from the OEC. It is found that an effective Coupled Dimer magnetic organisation of the four Mn in the OEC cluster in the S2 and S3 states is able to quantitatively rationalise the observed 55Mn hyperfine data. This is consistent with structures we propose to represent the likely state of the OEC in the catalytically active form of the enzyme.
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      PubDate: 2016-04-09T02:21:12Z
       
  • Synthesis, characterisation and biological activities of semicarbazones
           and their copper complexes
    • Abstract: Publication date: Available online 8 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Taracad K. Venkatachalam, Paul V. Bernhardt, Chris J. Noble, Nicholas Fletcher, Gregory K. Pierens, Kris J. Thurecht, David C. Reutens
      Substituted semicarbazones/thiosemicarbazones and their copper complexes have been prepared and several single crystal structures examined. The copper complexes of these semicarbazone/thiosemicarbazones were prepared and several crystal structures examined. The single crystal X-ray structure of the pyridyl-substituted semicarbazone showed two types of copper complexes, a monomer and a dimer. We also found that the p-nitrophenyl semicarbazone formed a conventional ‘magic lantern’ acetate-bridged dimer. Electron Paramagnetic Resonance (EPR) of several of the copper complexes were consistent with the results of single crystal X-ray crystallography. The EPR spectra of the p-nitrophenyl semicarbazone copper complex in dimethylsulfoxide (DMSO) showed the presence of two species, confirming the structural information. Since thiosemicarbazones and semicarbazones have been reported to exhibit anticancer activity, we examined the anticancer activity of several of the derivatives reported in the present study and interestingly only the thiosemicarbazone showed activity while the semicarbazones were not active indicating that introduction of sulphur atom alters the biological profile of these thiosemicarbazones.
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      PubDate: 2016-04-09T02:21:12Z
       
  • AGHLDDLPGALSAL: A hemoglobin fragment potentially competing with albumin
           to bind transition metal ions
    • Abstract: Publication date: Available online 8 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Giulia Zamariola, Joanna Watly, Eleonora Gallerani, Riccardo Gavioli, Remo Guerrini, Henryk Kozlowski, Maurizio Remelli
      Protein degradation leads to the formation of endogenous peptides, the biological activity of which is most often unknown. The peptide AGHLDDLPGALSAL, recently isolated from mouse brain homogenates, has been recognized as a fragment of the α-chain of hemoglobin. AGHLDDLPGALSAL has the ability of inhibiting the peripheral hyperalgesic inflammatory responses through the indirect activation of the μ-opioid receptors. A peculiarity of AGHLDDLPGALSAL is the presence, at its N-terminus of a strong binding site for divalent transition metal ions, similar to that characterizing the human albumin and called “ATCUN motif”. The consequential metal binding ability of AGHLDDLPGALSAL can be connected to its biological activity. For this reason, we decided to investigate the coordination properties of AGHLDDLPGALSAL towards Cu(II), Ni(II) and Zn(II) ions, reported here for the first time. The results confirm that AGHLDDLPGALSAL is a strong ligand for those metals: it can even compete with albumin under suitable conditions. In vitro assays on the inhibition of Cu(II) toxicity towards different cell lines confirmed that the binding ability of AGHLDDLPGALSAL can imply relevant biological consequences.
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      PubDate: 2016-04-09T02:21:12Z
       
  • Metalloprobes: Fluorescence imaging of multidrug resistance (MDR1)
           P-Glycoprotein (Pgp)-mediated functional transport activity in cellulo
    • Abstract: Publication date: June 2016
      Source:Journal of Inorganic Biochemistry, Volume 159
      Author(s): G.S.M. Sundaram, Monica Sharma, Daniel Kaganov, Junsang Cho, Scott E. Harpstrite, Vijay Sharma
      Radiolabeled metalloprobes offer sensitive tools for evaluating quantitative accumulation of chemical entities within pooled cell populations. Although beneficial in translational nuclear imaging, this method precludes interrogation of effects resulting from variations at a single cell level, within the same segment of cell population. Compared with radiotracer bioassays, fluorescence imaging offers a cost-efficient technique to assess accumulation of metalloprobes at a single cell level, and determine their intracellular localization under live cell conditions. To evaluate, whether or not radiotracer assay and fluorescence imaging provide complementary information on utility of metalloprobes to assess functional expression of P-glycoprotein (Pgp) on plasma membrane of tumor cells, imaging studies of fluorescent cationic Ga(III)-ENBDMPI (bis(3-ethoxy-2-hydroxy-benzylidene)-N,N′-bis(2,2-dimethyl-3-amino-propyl)ethylenediamine) and its neutral counterpart Zn(II)-ENBDMPI are performed. While the uptake profiles of the cationic metalloprobe are inversely proportional to expression of Pgp in tumor cells, the accumulation profiles of the neutral Zn(II)-ENBDMPI in non-MDR and MDR cells are not significantly impacted. The cationic Ga(III)-ENBDMPI maps with Mito-Tracker Red, thereby confirming localization within mitochondria of non-MDR (Pgp−) cells. Depolarization of both plasmalemmal and mitochondrial potentials decreased retention of the cationic Ga(III)-ENBDMPI within the mitochondria. Additionally, LY335979, an antagonist-induced accumulation of the cationic Ga(III) metalloprobe in MDR (Pgp+) cells indicated specificity of the agent. Compared with traits of Ga(III)-ENBDMPI as a Pgp recognized substrate, Zn(II)-ENBDMPI demonstrated uptake in both MDR and non-MDR cells thus indicating the significance of overall molecular charge in mediating Pgp recognition profiles. Combined data indicate that live cell imaging can offer a cost-effective methodology for monitoring functional Pgp expression.
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      PubDate: 2016-03-31T22:38:14Z
       
  • Cationic Pd(II) complexes acting as topoisomerase II inhibitors:
           Synthesis, characterization, DNA interaction and cytotoxicity
    • Abstract: Publication date: Available online 14 March 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Fillipe V. Rocha, Carolina V. Barra, Saulo S. Garrido, Francine.A. Manente, Iracilda Z. Carlos, Javier Ellena, Andrea S.C. Fuentes, Arnaud Gautier, Laurent Morel, Antonio E. Mauro, Adelino V.G. Netto

      Graphical abstract image

      PubDate: 2016-03-15T18:42:48Z
       
  • The Inorganic Perspective of VEGF: Interactions of Cu2+ with Peptides
           Encompassing a Recognition Domain of the VEGF Receptor
    • Abstract: Publication date: Available online 15 March 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Giulia Grasso, Anna Maria Santoro, Antonio Magrì, Diego La Mendola, Marianna Flora Tomasello, Stefania Zimbone, Enrico Rizzarelli
      The vascular endothelial growth factor A (VEGF-A) is a potent angiogenic factor, its activity may be influenced by the presence of copper(II) ions. To mimic the interaction between copper(II) and VEGF (vascular endotelial growth factor), the N- and C-terminally blocked peptide fragments VEGF73-101 and VEGF84-101, owing to VEGF165 protein, have been synthesized. These protein domains represent a specific recognition site with the VEGF receptor (VEGFR). Copper(II) complexes with VEGF73-101 and VEGF84-101 were investigated by means of potentiometry and UV-Vis, ESI-MS, CD, EPR spectroscopic methods. Both peptides have three histidine residues and display a binding high affinity for copper(II) ions. The proliferative activity of the peptides in the absence and presence of copper(II) ions as well as of VEGF-165 protein was also tested on HUVEC cells (Human Umbilical Vein Endothelial Cells). The VEGF73-101 showed a dose-dependent anti-proliferative activity, while the shorter peptide VEGF84-101 did not affect HUVEC proliferation, both in the presence and in the absence of VEGF.
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      PubDate: 2016-03-15T18:42:48Z
       
  • The synthesis, lipophilicity and cytotoxic effects of new ruthenium(II)
           arene complexes with chromone derivatives
    • Abstract: Publication date: June 2016
      Source:Journal of Inorganic Biochemistry, Volume 159
      Author(s): Adam Pastuszko, Kinga Majchrzak, Malgorzata Czyz, Bogumiła Kupcewicz, Elzbieta Budzisz
      A series of arene ruthenium(II) complexes with the general formula [(η6 −arene)Ru(L)X2] (where arene= p-cymene, benzene, hexamethylbenzene or mesitylene, L=aminoflavone or aminochromone derivatives and X=Cl, I) were synthesized and characterized by elemental analysis, MS, IR and 1H NMR spectroscopy. The stability of the selected complexes was assessed by UV–Vis spectroscopy in 24-hour period. The lipophilicity of the synthesized complexes was determined by the shake-flask method, and their cytotoxicity evaluated in vitro on patient-derived melanoma populations. The most active complexes against melanoma cells contain 7-aminoflavone and 6-aminoflavone as a ligand. The relationship between the cytotoxicity of all the obtained compounds and their logP values was determined and briefly analyzed with two different patterns observed.
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      PubDate: 2016-03-15T18:42:48Z
       
  • New photosensitive nanometric graphite oxide composites as antimicrobial
           material with prolonged action
    • Abstract: Publication date: June 2016
      Source:Journal of Inorganic Biochemistry, Volume 159
      Author(s): Y. Gerasymchuk, A. Lukowiak, A. Wedzynska, A. Kedziora, G. Bugla-Ploskonska, D. Piatek, T. Bachanek, V. Chernii, L. Tomachynski, W. Strek
      A new conjugate material based on partially reduced graphite oxide (rGO), silver nanoparticles (Ag), and bis(lysinato)zirconium(IV) phthalocyanine complex (ZrPc) was obtained. Its optical properties (absorption and photoluminescence) after dispersion in solvents were examined. The antimicrobial properties were tested to determine the effect of the composite on the following bacterial strains: Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, which are responsible for many infections and are one of the pathogens the most difficult to treatment. The results obtained for rGO–ZrPc–Ag composite were compared with the properties of GO, GO–ZrPc, and rGO–Ag structures. The influence of the near-infrared irradiation on the antimicrobial activity of ZrPc- and Ag-doped materials against bacteria was observed for very low concentration (0.32mg/mL) of GO–ZrPc to stop the growth of P. aeruginosa in comparison to the nonirradiated sample (41mg/mL). The usefulness of this material in therapy, such as wound infection treatment or endodontic treatment, as antibacterial agent with sustained action was discussed.
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      PubDate: 2016-03-15T18:42:48Z
       
  • Elucidation of the binding sites of two novel Ru(II) complexes on bovine
           serum albumin
    • Abstract: Publication date: Available online 2 March 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Marija Nišavić, Romana Masnikosa, Ana Butorac, Kristina Perica, Ana Rilak, Lela Korićanac, Amela Hozić, Marijana Petković, Mario Cindrić
      Hyphenated mass spectrometry (MS) techniques have attained an important position in analysis of covalent and non-covalent interactions of metal complexes with peptides and proteins. The aim of the present study was to qualitatively and quantitatively determine ruthenium binding sites on a protein using tandem mass spectrometry and allied techniques, i.e. liquid chromatography (LC) and inductively coupled plasma optical emission spectrometry (ICP-OES). For that purpose, two newly synthesized Ru(II) complexes of a meridional geometry, namely mer-[Ru(4′ Cl-tpy)(en)Cl]+ (1) and mer-[Ru(4′ Cl-tpy)(dach)Cl]+ (2) (where 4′ Cl-tpy=4′-chloro-2,2′:6′,2″-terpyridine, en=1,2-diaminoethane and dach =1,2-diaminocyclohexane), and bovine serum albumin were used. The binding of the complexes to the protein was investigated by means of size exclusion- and reversed phase-LC, ICP OES, matrix-assisted laser desorption ionization MS and MS/MS. Ruthenated peptide sequence and a binding target amino acid were revealed through accurate elucidation of MS/MS spectra. The results obtained in this study suggest a high binding capacity of the protein towards both complexes, with up to 5.77±0.14 and 6.95±0.43mol of 1 and 2 bound per mol of protein, respectively. The proposed binding mechanism for the selected complexes includes the release of Cl ligand, its replacement with water molecule and further coordination to electron donor histidine residue.
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      PubDate: 2016-03-07T18:19:05Z
       
  • Water-soluble and photo-stable silver(I) dicarboxylate complexes
           containing 1,10-phenanthroline ligands: Antimicrobial and anticancer
           chemotherapeutic potential, DNA interactions and antioxidant activity
    • Abstract: Publication date: Available online 2 March 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Laura Thornton, Vidya Dixit, Letícia O.N. Assad, Thales P. Ribeiro, Daniela D. Queiroz, Andrew Kellett, Alan Casey, John Colleran, Marcos D. Pereira, Garret Rochford, Malachy McCann, Denis O'Shea, Rita Dempsey, Siobhán McClean, Agnieszka Foltyn-Arfa Kia, Maureen Walsh, Bernadette Creaven, Orla Howe, Michael Devereux
      The complexes [Ag2(OOC-(CH2)n-COO)] (n=1–10) (1–10) were synthesised and reacted with 1,10-phenanthroline (phen) to yield derivatives formulating as [Ag2(phen)x(OOC-(CH2)y-COO)].zH2O (x=2 or 3; y=1–10; z=1–4) (11–20) which are highly water-soluble and photo-stable in aqueous solution. The phen derivatives 11–20 exhibit chemotherapeutic potential against C. albicans, E. coli, S. aureus and P. aeruginosa and against cisplatin-sensitive breast (MCF-7) and resistant ovarian (SKOV-3) cancer cell lines. Cyclic voltammetric analysis and DNA binding and intercalation studies indicate that the mechanism of action of 11–20 is significantly different to that of their silver(I) dicarboxylate precursors and they do not induce DNA damage or ROS generation in mammalian cells. The representative complexes 9 and 19 (containing the undecanedioate ligand) were both found to significantly reduce superoxide and hydrogen peroxide induced oxidative stress in the yeast S. cerevisiae.
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      PubDate: 2016-03-07T18:19:05Z
       
  • Tuning the geometry and biomimetic catalytic activity of
           manganese(III)-tetrabromocatecholate based robust platforms by introducing
           substitution at pyridine
    • Abstract: Publication date: Available online 2 March 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Narayan Ch. Jana, Paula Brandão, Anangamohan Panja
      The present report describes synthesis, characterization, crystal structures and catecholase activity of a series of five new manganese(III) complexes (1–5) derived from redox-noninnocent tetrabromocatecholate ligand in combination with different substituted pyridines. X-ray crystallography reveals that the geometry of manganese(III) centers in 1 and 2 is square pyramidal and they are pseudo-dimeric in the solid state resulting from the weak bonding of manganese(III) with a catecholate oxygen atom from the adjacent manganese(III) unit together with other weak interactions like hydrogen bonding and π···π stacking interactions. On the other hand, complexes 3–5 are discrete octahedral structures. All the complexes exhibit strong catecholase activity and their diverse catalytic activity can nicely be explained by the nature of substitution at pyridine ring – better electron donor inhibits the reduction of the metal center thereby lowering catecholase activity and vice versa (1 and 2 vs. 3–5). Besides the donor property of ancillary ligands, the structural distortion has also significant role in the biomimetic catalytic activity (1 vs. 2).
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      PubDate: 2016-03-07T18:19:05Z
       
  • Synthesis, Characterization, and Antitumor Activity of three Ternary
           Dinuclear Copper (II) Complexes with a Reduced Schiff base Ligand and
           Diimine Coligands in vitro and in vivo
    • Abstract: Publication date: Available online 4 March 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Lei Jia, Jun Xu, Xiaolei Zhao, Shanshan Shen, Tao Zhou, Zhouqing Xu, Taofeng Zhu, Ruhua Chen, Tieliang Ma, Jing Xie, Kun Dong, Jiancui Huang
      Three ternary copper (II) complexes containing 1,10-phenanthroline (phen, 1), dipyrido[3,2-d:2´,3´-f]quinoxaline (dpq, 2) and dipyrido[3,2-a:2´,3´-c]phenazine (dppz, 3), with the formulation [Cu2(NCL)2(H4PASP)]⋅4.5H2O (1-3) (where NCL = the diimine coligand, H4PASP = N,N'-(p-xylylene)di-2-aminosuccinic acid), were isolated and characterized. The binding of these complexes with calf thymus DNA was studied using UV-visible absorption titration, emission, and circular dichroism spectroscopy, among other methods. The changes in physicochemical properties that occurred upon binding of these complexes with DNA indicate that binding occurs primarily through intercalative interactions. Human tumor cell lines HeLa, PC3, and HepG2 were treated with the copper(II) complexes in vitro and cell survival rate was assessed by 3-(4,5-dimethyl thiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay and crystal violet survival assay. Flow cytometry was performed on treated cells labeled with AnnexinV/ Propidium Iodide staining to determine rates of apoptosis. Western blot was performed to determine the expression levels of the apoptotic markers p53, Bax, and Bcl-2. The complexes reduced cell viability and induced apoptosis in cells of human tumor cell lines in a dose-dependent manner. In addition, using a nude mouse xenograft model, we found that the three ternary copper (II) complexes inhibited human tumor cell growth in vivo. In conclusion, these novel synthetic copper complexes have profound antitumor effects on human tumor cells and are promising therapeutic agents for human tumors.
      Graphical abstract image

      PubDate: 2016-03-07T18:19:05Z
       
  • Mitochondria-targeted ruthenium (II) polypyridyl complexes with benzofuran
           group for live cell imaging
    • Abstract: Publication date: June 2016
      Source:Journal of Inorganic Biochemistry, Volume 159
      Author(s): Li Xu, Yu-Ying Liu, Liu-Ming Chen, Ye-Yi Xie, Jie-Xing Liang, Hui Chao
      Labeling and imaging mitochondria have attracted considerable interest because of its involvement in early stage apoptosis and necrotic cell death. Various highly specific and photostable fluorescent probes for mitochondria are in demand. In the present study, two novel Ru(II) polypyridine complexes Ru1 and Ru2 were developed to act as mitochondrial fluorescence probes. In comparison with the commercially available mitochondrial trackers, Ru1 possesses high mitochondria-specificity, superior photostability, high resistance to the loss of mitochondrial membrane potential and appreciable tolerance to environmental change, allowing imaging of the mitochondrial morphological changes over long periods of time. Combined results indicate that Ru1 may contribute to the future development of staining agents for organelle-selective imaging in living cells.
      Graphical abstract image

      PubDate: 2016-03-07T18:19:05Z
       
  • Calcium binding characteristics and structural changes of phosvitin
    • Abstract: Publication date: June 2016
      Source:Journal of Inorganic Biochemistry, Volume 159
      Author(s): Xiaowei Zhang, Fang Geng, Xi Huang, Meihu Ma
      Phosvitin is a unique highly phosphorylated protein that plays a role in the regulation of calcification. We conducted a comprehensive study of the chemical, thermodynamic and structural aspects of the interaction of phosvitin with calcium ions using a calcium ion selective electrode (ISE), isothermal titration calorimetry (ITC), circular dichroism spectrum (CD) and fluorescence spectroscopy, respectively. The results showed that under neutral and alkaline conditions, distinct high affinity and low affinity binding modes existed in the interaction between phosvitin and calcium. The high affinity association constant was approximately 104 mol−1, while the binding sites contained nearly 30mol of calcium per mole of phosvitin. This reaction was driven by enthalpy. The unordered and β-turn conformations of phosvitin increased, while the β-sheet conformation decreased. The main interaction forces were electrostatic force, hydrogen bonds or van der Waals force. The low affinity association constant and binding sites were not constant, as many calcium ions were sequestered by phosvitin. The binding reaction was driven by entropy, and the β-sheet conformation of phosvitin increased while the unordered conformation decreased. The main interaction force was hydrophobic force. However, under acidic conditions, the interaction between phosvitin and calcium was an entropy-driven endothermic reaction, and the main interaction force was weak hydrophobic force. This calcium-binding characteristic of phosvitin may play a specific role in its biological function.
      Graphical abstract image

      PubDate: 2016-03-07T18:19:05Z
       
  • Correlating the structures and activities of the resting oxidized and
           native intermediate states of a small laccase by paramagnetic NMR
    • Abstract: Publication date: Available online 11 February 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Michael C. Machczynski, Jeffrey T. Babicz
      Multicopper oxidases (MCO) are the fastest and most efficient known catalysts of the oxygen-reduction reaction. When all four copper ions are oxidized during catalysis, the native intermediate state (NI) decays in seconds to the resting oxidized state (RO), which returns to the catalytic cycle via reduction, but at a much slower rate than NI. We report the long-lived (months at 4 °C) NI state of the small laccase (SLAC) MCO and the subsequent characterization of both its RO and NI states by paramagnetic 1H NMR. We find that the RO state of the trinuclear cluster (TNC) is best described as an isolated Type-3 dicopper site, antiferromagnetically coupled by a hydroxo group with -2 J = 500 cm−1. The NI state is more complicated; we develop a theoretical treatment for the case in which all three copper ions in the TNC are coupled, and find that the results are consistent with three coupling constants of -2 J = 300, 240, and 160 cm−1. These couplings result in a ground doublet state, a low-lying excited doublet state at 121 cm−1, and a quartet excited state at 411 cm−1, in good agreement with DFT models in which the Type-2 copper has a terminal hydroxo ligand.
      Graphical abstract image

      PubDate: 2016-02-20T23:02:18Z
       
  • Glycosidase- and β-Lactamase-like Activity of Dinuclear Copper(II)
           Patellamide Complexes
    • Abstract: Publication date: Available online 13 February 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Peter Comba, Annika Eisenschmidt, Nora Kipper, Jasmin Schießl
      Prochloron, a blue-green algae belonging to ancient prokaryotes, produces, like other cyanobacteria, cyclic pseudo-peptides, which are also found in its obligate symbiont ascidiae (Lissoclinum patellum). Although research has focused for some time on the putative metabolic function of these cyclic peptides, to date it is still not understood. Their role might be connected to the increased concentrations of divalent metal ions, especially CuII, found in ascidiae. Dinuclear copper(II) complexes of cyclic pseudo-peptides revealed a broad hydrolytic capacity, including carboanhydrase and phosphatase activity. This study reports their β-lactamase as well as α- and β-glycosidase activity with k cat = (11.34±0.91)ˑ10-4 s-1 for β-lactamase, k cat = (1.55±0.13)ˑ10-4 s-1 for α-glycosidase and k cat = (1.22±0.09)ˑ10-4 s-1 for β-glycosidase activity.
      Graphical abstract image

      PubDate: 2016-02-16T22:43:25Z
       
  • A Mn(II) complex of boradiazaindacene (BODIPY) loaded graphene oxide as
           both LED light and H2O2 enhanced anticancer agent
    • Abstract: Publication date: Available online 13 February 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Xiao-Lei Xu, Jian Shao, Qiu-Yun Chen, Cheng-Hao Li, Meng-Yun Kong, Fang Fang, Ling Ji, Daniel Boison, Tao Huang, Jing Gao, Chang-Jian Feng
      Cancer cells are more susceptible to H2O2 induced cell death than normal cells. H2O2-activatable and O2-evolving nanoparticles could be used as photodynamic therapy agents in hypoxic environments. In this report, a photo-active Mn(II) complex of boradiazaindacene derivatives (Mn1) was used as a dioxygen generator under irradiation with LED light in water. Moreover, the in vitro biological evaluation for Mn1 and its loaded graphene oxide (herein called Mn1@GO) on HepG-2 cells in normal and hypoxic conditions has been performed. In particular, Mn1@GO can react with H2O2 resulting active anticancer species, which show high inhibition on both HepG-2 cells and CoCl2-treated HepG-2 cells (hypoxic cancer cells). The mechanism of LED light enhanced anticancer activity for Mn1@GO on HepG-2 cells was discussed. Our results show that Mn(II) complexes of boradiazaindacene (BODIPY) derivatives loaded GO can be both LED light and H2O2-activated anticancer agents in hypoxic environments.
      Graphical abstract image

      PubDate: 2016-02-16T22:43:25Z
       
  • Topoisomerase I inhibition and DNA cleavage by zinc, copper, and nickel
           derivatives of 2-[2-bromoethyliminomethyl]-4-[ethoxymethyl]phenol
           complexes exhibiting anti-proliferation and anti-metastasis activity
    • Abstract: Publication date: Available online 11 February 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Sze Koon Lee, Wai Tan Kong, Seik Weng Ng
      Three transition metal derivatives (Zn, Cu, and Ni) of 2-[2-bromoethyliminomethyl]-4-[ethoxymethyl]phenol (L) were synthesized by the reaction of the metal salts with the Schiff base ligand in one pot. In the crystal structure of [Zn(L)Br], the Schiff base ligand binds to the metal center through its phenolate oxygen and imine nitrogen, and adopts a distorted tetrahedral geometry. These compounds were found to inhibit topoisomerase I (topo I) activity, induce DNA cleavage and show DNA binding activity. Moreover, these compounds were found to be cytotoxic towards several cancer cell lines (A2780, MCF-7, HT29, HepG2, A549, PC3, LNCaP) and prevent metastasis of PC3. Collectively, Cu(II) complex 2 shows superior activity relative to its Zn(II) and Ni(II) analogues.
      Graphical abstract image

      PubDate: 2016-02-12T22:36:58Z
       
  • Copper(I) stabilization by cysteine/tryptophan motif in the extracellular
           domain of Ctr4
    • Abstract: Publication date: Available online 11 February 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Mariko Okada, Takashi Miura
      Copper transporter Ctr4 of fission yeast has a quasi-palindromic sequence rich in cysteine and aromatic amino acid residues, CX4YWNWYX4C (where X represents any amino acid), in the N-terminal extracellular domain. A 24-mer peptide comprising this sequence is bound to Cu(I) through the cysteine thiolate coordination. Luminescence, UV absorption and resonance Raman spectra of the Cu(I)-peptide complex show that at least one of the two tryptophan side chains is located in close proximity to the thiolate-Cu(I) center and interacts with the Cu(I) ion via π-electrons of the indole ring. Although the thiolates and Cu(I) are oxidized to disulfide and Cu(II), respectively, only very slowly in air-saturated solutions, replacements of the tryptophan residues to phenylalanine significantly accelerate the oxidation reactions. The results obtained indicate that the interaction between Cu(I) and tryptophan via π-electrons plays a significant role in protecting the thiolate-Cu(I) center against the oxidation. The cysteine- and tryptophan-rich quasi-palindromic sequence may be a metal binding motif that stabilizes Cu(I) in the oxidizing extracellular environment.
      Graphical abstract image

      PubDate: 2016-02-12T22:36:58Z
       
  • Investigation of the binding of cis/trans-[MCl4(1H-indazole)(NO)]−
           (M = Ru, Os) complexes to human serum albumin
    • Abstract: Publication date: Available online 11 February 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Orsolya Dömötör, Anna Rathgeb, Paul-Steffen Kuhn, Ana Popović-Bijelić, Goran Bačić, Eva Anna Enyedy, Vladimir B. Arion
      Overall binding affinity of sodium or indazolium cis/trans-[MCl4(1H-indazole)(NO)] (M = Ru, Os) complexes towards human serum albumin (HSA) and high molecular mass components of the blood serum was monitored by ultrafiltration. HSA was found to be mainly responsible for the binding of the studied ruthenium and osmium complexes. In other words, this protein can provide a depot for the compounds and can affect their biodistribution and transport processes. In order to elucidate the HSA binding sites tryptophan fluorescence quenching studies and displacement reactions with the established site markers warfarin and dansylglycine were performed. Conditional stability constants for the binding to sites I and II on HSA were computed showing that the studied ruthenium and osmium complexes are able to bind into both sites with moderately strong affinity (logK’ = 4.4–5.1). Site I is slightly more favored over site II for all complexes. No significant differences in the HSA binding properties were found for these metal complexes demonstrating negligible influence of the type of counter ion (sodium vs. indazolium), the metal ion center identity (Ru vs. Os) or the position of the nitrosyl group on the binding event. Electron paramagnetic resonance spin labeling of HSA revealed that indazolium trans-[RuCl4(1H-indazole)(NO)] and long-chain fatty acids show competitive binding to HSA. Moreover, this complex has a higher affinity for site I, but when present in excess, it is able to bind to site II as well, and displace fatty acids.
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      PubDate: 2016-02-12T22:36:58Z
       
  • Synthesis, characterization, antiproliferative and molecular docking study
           of new half sandwich Ir(III), Rh(III) and Ru(II) complexes
    • Abstract: Publication date: Available online 12 February 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Saravanan Thangavel, Manickam Paulpandi, Holger B. Friedrich, Kadarkarai Murugan, Kalva Sukesh, Adam A. Skelton
      The new carbazole N,N′ ligand containing [(η 5-C5Me5)MCl(L)]PF6, (M=Ir (1) and Rh (2)) and [(η 6-C6H6)RuCl(L)]PF6 (3) (C5Me5 =pentamethylcyclopentadienyl, L =9-ethyl-N-(pyridine-2-yl methylene)-9H-carbazole-3-amine) complexes has been synthesized and characterized by 1H NMR, 13C NMR, 2D NMR, melting point analysis, electronic absorption, infrared spectroscopy, HR-Mass spectroscopy and elemental analyses. The crystal structure of the [(η 5-C5Me5)RhCl(L)]PF6 has been confirmed by single crystal XRD. The anticancer study of the synthesized complexes 1–3 clearly showed a potent inhibitor of human breast cancer cells (MCF-7) under in vitro conditions. The inhibitory concentrations (IC50) of the complexes 1–3 were determined at low (5, 6 and 8μM) concentration against the MCF-7 human breast cancer cell line. Further cytotoxic, cell cycle and nuclear studies confirmed that the novel half sandwich Ir(III), Rh(III) and Ru(II) complexes could be effective against MCF-7 human breast cancer cell proliferation. Moreover the results indicate that anticancer in vitro activity of complexes 1–3 falls in the order of 1 > 2 > 3. A molecular docking study of the complexes 1–3 showed the nature of binding energy, H-bond and hydrophobic interactions with the cyclooxygenase-2 (COX-2) receptor.
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      PubDate: 2016-02-12T22:36:58Z
       
  • Unbound Position II in MXCXXC Metallochaperone Model Peptides Impacts
           Metal Binding Mode and Reactivity: Distinct Similarities to Whole Proteins
           
    • Abstract: Publication date: Available online 12 February 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Michal S. Shoshan, Noa Dekel, Wojciech Goch, Deborah E. Shalev, Tsafi Danieli, Mario Lebendiker, Wojciech Bal, Edit Y. Tshuva
      The effect of position II in the binding sequence of copper metallochaperones, which varies between Thr and His, was investigated through structural analysis and affinity and oxidation kinetic studies of model peptides. A first Cys-Cu(I)-Cys model obtained for the His peptide at acidic and neutral pH, correlated with higher affinity and more rapid oxidation of its complex; in contrast, the Thr peptide with the Cys-Cu(I)-Met coordination under neutral conditions demonstrated weaker and pH dependent binding. Studies with human antioxidant protein 1 (Atox1) and three of its mutants where S residues were replaced with Ala suggested that (a) the binding affinity is influenced more by the binding sequence than by the protein fold (b) pH may play a role in binding reactivity, and (c) mutating the Met impacted the affinity and oxidation rate more drastically than did mutating one of the Cys, supporting its important role in protein function. Position II thus plays a dominant role in metal binding and transport.
      Graphical abstract image

      PubDate: 2016-02-12T22:36:58Z
       
  • Protein-based ferrogels
    • Abstract: Publication date: Available online 12 February 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Puja Mody, Cassidy Hart, Siena Romano, Mariam El-Magbri, Moira M. Esson, Trisha Ibeh, Elizabeth D. Knowlton, Ming Zhang, Michael J. Wagner, Matthew R. Hartings
      We present a novel synthesis in which hemoglobin and Fe2+ react, in the presence of KNO3 and KOH, to produce protein microgels that contain magnetic iron oxide nanoparticles. The synthesis results in microgels with polymer properties (denaturing and glass transition temperatures) that are consistent with the dried protein. The iron oxide nanoparticles exhibit an average diameter of 22 nm, are ferrimagnetic, and display properties consistent with Fe3O4. The multiple functional capabilities displayed by these materials: biocompatibility, magnetism, dye uptake and controlled release, and other properties archetypal of hydrogels, will make the magnetic hydrogels attractive for a number of biomedical applications.
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      PubDate: 2016-02-12T22:36:58Z
       
  • Synthesis, structures and Helicobacter pylori urease inhibitory activity
           of copper(II) complexes with tridentate aroylhydrazone ligands
    • Abstract: Publication date: Available online 12 February 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Lin Pan, Cunfang Wang, Kai Yan, Kedong Zhao, Guihua Sheng, Hailiang Zhu, Xinlu Zhao, Dan Qu, Fang Niu, Zhonglu You
      A series of new copper(II) complexes were prepared. They are [CuL1(NCS)] (1), [CuClL1]·CH3OH (2), [CuClL2]·CH3OH (3), [CuL3(NCS)]·CH3OH (4), [CuL4(NCS)]·0.4H2O (5), and [CuL5(bipy)] (6), where L1, L2, L3 and L4 are the deprotonated form of N’-(2-hydroxybenzylidene)-3-methylbenzohydrazide, 4-bromo-N’-(2-hydroxy-5-methoxybenzylidene)benzohydrazide, N’-(2-hydroxy-5-methoxybenzylidene)-3-methylbenzohydrazide and 2-chloro-N’-(2-hydroxy-5-methoxybenzylidene)benzohydrazide, respectively, L5 is the dianionic form of N’-(2-hydroxybenzylidene)-3-methylbenzohydrazide, and bipy is 2,2’-bipyridine. The complexes were characterized by infrared and UV-Vis spectra, and single crystal X-ray diffraction. The Cu atoms in complexes 1, 2, 3, 4 and 5 are coordinated by the NOO donor set of the aroylhydrazone ligands, and one Cl or thiocyanate N atom, forming square planar coordination. The Cu atom in complex 6 is in a square pyramidal coordination, with the NOO donor set of L1, and one N atom of bipy defining the basal plane, and with the other N atom of bipy occupying the apical position. Complexes 1, 2, 3, 4 and 5 show effective urease inhibitory activities, with IC50 values of 5.14, 0.20, 4.06, 5.52 and 0.26 μM, respectively. Complex 6 has very weak activity against urease, with IC50 value over than 100 μM. Molecular docking study of the complexes with the Helicobacter pylori urease was performed. The relationship between structures and urease inhibitory activities indicated that copper complexes with square planar coordination are better models for urease inhibition.
      Graphical abstract image

      PubDate: 2016-02-12T22:36:58Z
       
 
 
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