for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> CHEMISTRY (Total: 845 journals)
    - ANALYTICAL CHEMISTRY (47 journals)
    - CHEMISTRY (596 journals)
    - CRYSTALLOGRAPHY (22 journals)
    - ELECTROCHEMISTRY (26 journals)
    - INORGANIC CHEMISTRY (42 journals)
    - ORGANIC CHEMISTRY (45 journals)
    - PHYSICAL CHEMISTRY (67 journals)

INORGANIC CHEMISTRY (42 journals)

Showing 1 - 0 of 0 Journals sorted alphabetically
Acta Polymerica     Hybrid Journal   (Followers: 7)
Additives for Polymers     Full-text available via subscription   (Followers: 20)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Polymer Technology     Hybrid Journal   (Followers: 12)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 3)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 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: 40)
Heterocyclic Communications     Hybrid Journal  
High Performance Polymers     Hybrid Journal  
Indian Journal of Chemistry - Section A     Open Access   (Followers: 7)
Inorganic Chemistry     Full-text available via subscription   (Followers: 19)
Inorganic Chemistry Communications     Hybrid Journal   (Followers: 9)
Inorganic Chemistry Frontiers     Full-text available via subscription   (Followers: 1)
Inorganic Materials     Hybrid Journal   (Followers: 3)
Inorganic Materials: Applied Research     Hybrid Journal   (Followers: 1)
Inorganica Chimica Acta     Hybrid Journal   (Followers: 6)
Inorganics     Open Access  
International Journal of Bio-Inorganic Hybrid Nanomaterials     Open Access  
International Journal of Inorganic Chemistry     Open Access   (Followers: 1)
JBIC Journal of Biological Inorganic Chemistry     Hybrid Journal   (Followers: 4)
Journal of Inorganic and Organometallic Polymers and Materials     Partially Free   (Followers: 6)
Journal of Inorganic Biochemistry     Hybrid Journal   (Followers: 3)
Journal of Inorganic Chemistry     Open Access   (Followers: 3)
Journal of Polymer Engineering     Hybrid Journal   (Followers: 8)
Journal of Polymers and the Environment     Hybrid Journal   (Followers: 1)
Journal of Separation Science     Hybrid Journal   (Followers: 11)
Metallodrugs     Open Access   (Followers: 1)
Open Journal of Inorganic Chemistry     Open Access   (Followers: 2)
Plasmas and Polymers     Hybrid Journal  
Polymer Bulletin     Hybrid Journal   (Followers: 7)
Polymer Composites     Hybrid Journal   (Followers: 13)
Polyoxometalate Chemistry     Open Access  
Reviews in Inorganic Chemistry     Hybrid Journal  
Russian Journal of Inorganic Chemistry     Hybrid Journal  
Studies in Inorganic Chemistry     Full-text available via subscription  
Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry     Hybrid Journal   (Followers: 2)
Topics in Inorganic and General Chemistry     Full-text available via subscription  
Zeitschrift für anorganische und allgemeine Chemie     Hybrid Journal   (Followers: 2)
Zeitschrift für Kristallographie - New Crystal Structures     Open Access  
Journal Cover Journal of Inorganic Biochemistry
  [SJR: 0.96]   [H-I: 87]   [3 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0162-0134
   Published by Elsevier Homepage  [2970 journals]
  • A comparative study on the interactions of human copper chaperone Cox17
           with anticancer organoruthenium(II) complexes and cisplatin by mass
           spectrometry
    • Abstract: Publication date: Available online 15 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Lijie Li, Wei Guo, Kui Wu, Xuelei Wu, Linhong Zhao, Yao Zhao, Qun Luo, Yuanyuan Wang, Yangzhong Liu, Qingwu Zhang, Fuyi Wang
      Herein we report investigation of the interactions between anticancer organoruthenium complexes, [(η6-arene)Ru(en)(Cl)]PF6 (en=ethylenediamine, arene= p-cymene (1) or biphenyl (2)), and the human copper chaperone protein Cox17 by mass spectrometry with cisplatin as a reference. The electrospray ionization mass spectrometry (ESI-MS) results indicate much weaker binding of the ruthenium complexes than that of cisplatin to apo-Cox172s-s, the functional state of Cox17. Up to tetra-platinated Cox17 adducts were identified while only mono-ruthenated and a little amount of di-ruthenated Cox17 adducts were detected even for the reactions with 10-fold excess of the Ru complexes. However, ESI-MS analysis coupled with liquid chromatography of tryptic digests of metalated proteins identified only three platination sites as Met4, Cys27 and His47 residues, possibly due to the lower abundance or facile dissociation of Pt bindings at other sites. Complexes 1 and 2 were found to bind to the same three residues with Met4 as the major site. Inductively coupled plasma mass spectrometry results revealed that ~7mol Pt binding to 1mol apo-Cox172s-s molecules, compared to only 0.17 (1) and 0.10 (2) mol Ru to 1mol apo-Cox172s-s. This is in line with the circular dichroism results that much larger unfolding extent of α-helix of apo-Cox172s-s was observed upon cisplatin binding than that upon organoruthenium bindings. These results collectively indicate that Cox17 might not participate in the action of these anticancer organoruthenium complexes, and further verify the distinct anticancer mechanism of the organoruthenium(II) complexes from cisplatin.
      Graphical abstract image

      PubDate: 2016-05-19T05:11:26Z
       
  • Prochelator strategies for site-selective activation of metal chelators
    • Abstract: Publication date: Available online 17 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Valentina Oliveri, Graziella Vecchio
      Metal dyshomeostasis has been involved in the etiology of a host of pathologies such as Wilson’s, Alzheimer’s, Parkinson’s, Huntington’s, transfusion-related iron overload diseases and cancer. Although metal chelating agents represent a necessary therapeutic strategy in metal overload diseases, long-term use of strong chelators that are not selective, can be anticipated perturbing normal physiological functions of essential metal-requiring biomolecules. In this context, the last decade has seen a growing interest in the development of molecules, referred to as “prochelators”, that have little affinity for metal ions until they are activated in response to specific stimuli. Here, we present the main strategies applied to develop safe prochelators and focus on chosen examples to provide an overview of this field to date.
      Graphical abstract image

      PubDate: 2016-05-19T05:11:26Z
       
  • G-quadruplex vs. duplex-DNA binding of nickel(II) and zinc(II) Schiff base
           complexes
    • Abstract: Publication date: Available online 14 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Riccardo Bonsignore, Alessio Terenzi, Angelo Spinello, Annamaria Martorana, Antonino Lauria, Anna Maria Almerico, Bernhard K. Keppler, Giampaolo Barone
      Novel nickel(II) (1) and zinc(II) (2) complexes of a Salen-like ligand, carrying a pyrimidine ring on the N,N′ bridge, were synthesized and characterized. Their interaction with duplex and G-quadruplex DNA was investigated in aqueous solution through UV–visible absorption, circular dichroism and viscometry measurements. The results obtained point out that, while the zinc(II) complex does not interact with both duplex and G-quadruplex DNA, the nickel(II) complex 1 binds preferentially to G-quadruplex respect to duplex-DNA, with values of the DNA-binding constants, K b , 2.6✕105 M−1 and 3.5✕104 M−1, respectively. Molecular dynamics simulations provided an atomic level model of the top-stacking binding occurring between 1 and hTelo G-quadruplex.
      Graphical abstract image

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

      PubDate: 2016-05-19T05:11:26Z
       
  • Revised stability constant, spectroscopic properties and binding mode of
           Zn(II) to FluoZin-3, the most common zinc probe in life sciences
    • Abstract: Publication date: Available online 13 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): I. Marszałek, A. Krężel, W. Goch, I. Zhukov, I. Paczkowska, W. Bal
      2-[2-[2-[2-[bis(carboxylatomethyl)amino]-5-methoxyphenoxy]ethoxy]-4-(2,7-difluoro-3-oxido-6-oxo-4a,9a-dihydroxanthen-9-yl)anilino]acetate (FluoZin-3) is used very broadly in life sciences as intra- and extracellular Zn(II) sensor selective for Zn(II) over Co(II), Ca(II) and Mg(II) ions at their physiological concentrations. It has been used for determination of relative and absolute levels of exchangeable Zn(II) in cells and extracellular fluids. Despite its popularity, the knowledge of its acid/base and Zn(II) coordination abilities and of its spectroscopic properties remained very limited. Also the published conditional dissociation constant (C K d) values at pH7.4 are slightly discrepant, (15nM or 8.9nM). In this work we determined the C K d for Zn(II) complexation by FluoZin-3 at pH7.4 with nitrilotriacetic acid (NTA) as competitor using two independent methods: fluorimetry and UV–Vis spectroscopy. For the first time, we investigated FluoZin-3 alone and complexed with Zn(II) in the wide range of pH, determining the total of eight pK a values from fluorescence spectra and from various regions of UV–Vis spectra. The validated values of C K d (9.1±0.4nM; −log C K d =8.04) and of the absolute (pH-independent) stability constant log βZnL (8.16±0.05) were provided by fluorescence spectroscopy experiments performed at 1μM concentrations. Our experiments demonstrated that both of aminocarboxylate moieties of FluoZin-3 bind the Zn(II) ion synergistically.
      Graphical abstract image

      PubDate: 2016-05-14T04:43:16Z
       
  • The (unusual) aspartic acid in the metal coordination sphere of the
           prokaryotic zinc finger domain
    • Abstract: Publication date: Available online 11 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Gianluca D'Abrosca, Luigi Russo, Maddalena Palmieri, Ilaria Baglivo, Fortuna Netti, Ivan de Paola, Laura Zaccaro, Biancamaria Farina, Rosa Iacovino, Paolo Vincenzo Pedone, Carla Isernia, Roberto Fattorusso, Gaetano Malgieri
      The possibility of choices of protein ligands and coordination geometries leads to diverse Zn(II) binding sites in zinc-proteins, allowing a range of important biological roles. The prokaryotic Cys2His2 zinc finger domain (originally found in the Ros protein from A. tumefaciens) tetrahedrally coordinates zinc through two cysteine and two histidine residues and it does not adopt a correct fold in the absence of the metal ion. Ros is the first structurally characterized member of a family of bacterial proteins that presents several amino acid changes in the positions occupied in Ros by the zinc coordinating residues. In particular, the second position is very often occupied by an aspartic acid although the coordination of structural zinc by an aspartate in eukaryotic zinc fingers is very unusual. Here, by appropriately mutating the protein Ros, we characterize the aspartate role within the coordination sphere of this family of proteins demonstrating how the presence of this residue only slightly perturbs the functional structure of the prokaryotic zinc finger domain while it greatly influences its thermodynamic properties.
      Graphical abstract image

      PubDate: 2016-05-14T04:43:16Z
       
  • Tacrine-(hydroxybenzoyl-pyridone) hybrids as potential multifunctional
           anti-Alzheimer's agents: AChE inhibition, antioxidant activity and metal
           chelating capacity
    • Abstract: Publication date: Available online 13 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Karam Chand, Hesham M. Alsoghier, Sílvia Chaves, M. Amélia Santos
      Three novel potentially site-activated multitarget tacrine-(hydroxybenzoyl-pyridone) (TAC-HBP) hybrids were designed, synthesized and evaluated as acetylcholinesterase (AChE) inhibitors, antioxidants and biometal chelators. All of them are dual-binding site AChE inhibitors with activity in sub-micromolar range (IC50 =0.57–0.78μM), which is comparable to the parent tacrine, and have good 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity (EC50 =204–249μM) conferred by the hydroxybenzoyl-pyridone (HBP) moiety. Their chelating capacity towards redox-active and/or amyloid-β-binding metal ions (Fe(III), Cu(II)), Zn(II)) was evaluated by using 2′-hydroxy-4′-methoxybenzoyl-2-pyridone derivative as a model compound in 30% w/w DMSO/water medium. It was proved that the HBP moiety acts as a moderate/good chelator of these biometals (pFe=13.9, pCu=6.0 and pZn=6.0 at pH6.0, C L/C M =10, C M =10−6 M), being able to form complexes with β-phenol-keto coordination mode, and that this chelating ability is preserved in the TAC-HBP hybrids.
      Graphical abstract image

      PubDate: 2016-05-14T04:43:16Z
       
  • Targeting copper(II)-induced oxidative stress and the acetylcholinesterase
           system in Alzheimer's disease using multifunctional tacrine-coumarin
           hybrid molecules
    • Abstract: Publication date: Available online 5 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Slavka Hamulakova, Patrik Poprac, Klaudia Jomova, Vlasta Brezova, Peter Lauro, Lenka Drostinova, Daniel Jun, Vendula Sepsova, Martina Hrabinova, Ondrej Soukup, Pavol Kristian, Zuzana Gazova, Zuzana Bednarikova, Kamil Kuca, Marian Valko
      Alzheimer's disease is a multifactorial disease that is characterized mainly by Amyloid-β (A-β) deposits, cholinergic deficit and extensive metal (copper, iron)-induced oxidative stress. In this work we present details of the synthesis, antioxidant and copper-chelating properties, DNA protection study, cholinergic activity and amyloid-antiaggregation properties of new multifunctional tacrine-7-hydroxycoumarin hybrids. The mode of interaction between copper(II) and hybrids and interestingly, the reduction of Cu(II) to Cu(I) species (for complexes Cu-5e-g) were confirmed by EPR measurements. EPR spin trapping on the model Fenton reaction, using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trap, demonstrated a significantly suppressed formation of hydroxyl radicals for the Cu-5e complex in comparison with free copper(II). This suggests that compound 5e upon coordination to free copper ion prevents the Cu(II)-catalyzed decomposition of hydrogen peroxide, which in turn may alleviate oxidative stress-induced damage. DNA damage protection activity of hybrids 5c and 5e in a Fenton system (copper catalyzed) was found to be in excellent agreement with the EPR spin trapping study. Compound 5g was the most effective in the inhibition of acetylcholinesterase (hAChE, IC 50 =38nM) and compound 5b was the most potent inhibitor of butyrylcholinesterase (hBuChE, IC 50 =63nM). Compound 5c was the strongest inhibitor of A-β1–40 aggregation, although a significant inhibition (>50%) was detected for compounds 5b, 5d, 5e and 5g. Collectively, these results suggest that the design and investigation of multifunctional agents containing along with the acetylcholinesterase inhibitory segment also an antioxidant moiety capable of alleviating metal (copper)-induced oxidative stress, may be of importance in the treatment of Alzheimer's disease.
      Graphical abstract image

      PubDate: 2016-05-09T06:06:59Z
       
  • Synthesis, characterization and antitumoral activity of new
           cobalt(II)complexes: effect of the ligand isomerism on the biological
           activity of the complexes
    • Abstract: Publication date: Available online 8 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Samila R. Morcelli, Érika Stilobezzia bulla, Wagner S. Terra, Rafaela O. Moreira, Franz V. Borges, Milton M. Kanashiro, Adailton J. Bortoluzzi, Leide L.F. Maciel, João Carlos de A. Almeida, Adolfo Horn Júnior, Christiane Fernandes
      The synthesis, physico-chemical characterization and cytotoxicity against five human tumoral cell lines (THP-1, U937, Molt-4, Colo205 and H460) of three new cobalt(II) coordination compounds are reported (i.e. Co(HL1)Cl (1), Co(HL2)Cl (2) and [Co(HL3)Cl]0.0.5 (CH3)2CHOH (3)). H2L2 (2-{[[2-hydroxy-3-(1-naphthyloxy)propyl](pyridin-2-ylmethyl)amino]methyl}phenol) and H2L3 (2-{[[2-hydroxy-3-(2-naphthyloxy)propyl](pyridin-2-ylmethyl)amino]methyl}phenol) present α and β-naphthyl groups respectively, which is absent in H2L1 (N-(2-hydroxybenzyl)-N-(2-pyridylmethyl)[(3-chloro)(2-hydroxy)]propylamine.These compounds were characterized by a range of physico-chemical methods. X-ray diffraction studies were performed for complex (3), indicating the formation of a mononuclear complex. Complexes (2) and (3), which contain α and β-naphthyl groups respectively, have presented lower IC50 values than those exhibited by complex (1). Complex (3) presents IC50 values lower than cisplatin against Colo205 (90 and 196 μmol L−1, respectively) and H460 (147 and 197 μmol L−1, respectively). These human neoplastic cells under investigation were also more susceptible toward complex (3) than peripheral blood mononuclear cells. Transmission electron microscopy investigations are in agreement with the loss of mitochondrial membrane potential (ΔΨm) observed by JC-1 mitochondrial potential sensor and indicate that the activity of complex (3) against leukemic cell line (U937) is mediated by an apoptotic mechanism associated with mitochondrial dysfunction (intrinsic pathway).
      Graphical abstract image

      PubDate: 2016-05-09T06:06:59Z
       
  • Metals content of Glossoscolex paulistus extracellular hemoglobin: Its
           peroxidase activity and the importance of these ions in the protein
           stability
    • Abstract: Publication date: Available online 5 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Celia S. Caruso, Ezer Biazin, Francisco A.O. Carvalho, Marcel Tabak, José F.R. Bachega
      In this work we investigate the presence of divalent cations bound to the Glossoscolex paulistus (HbGp) hemoglobin and their effect over the protein stability and the peroxidase (POD) activity. Atomic absorption studies show that the HbGp iron content is consistent with the presence of 144 ions per protein. Moreover, using iron as a reference, the content of calcium was estimated as 30±4 ions per protein, independently of the EDTA pre-treatment or not prior to the acidic treatment performed in the protein digestion. The zinc content was 14±2 ions in the absence of EDTA pre-treatment, and 3±1 ions per protein in the presence of EDTA pre-treatment, implying the presence of one zinc ion per protomer (1/12 of the whole molecule). Finally, the copper concentration is negligible. Different from the vertebrate hemoglobins, where the effectors are usually organic anions, the hexagonal bilayer hemoglobins have as effectors inorganic cations that increase the oxygen affinity and stabilize the structure. Previous studies have suggested that the presence of divalent cations, such as copper and zinc, is related to the different types of antioxidant enzymatic activities as the superoxide dismutase (SOD) activity shown by giant hemoglobin from Lumbricus terrestris (HbLt). Recently, studies on HbGp crystal structure have confirmed the presence of Zn2+ and Ca2+ binding sites. The Ca2+ sites are similar as observed in the HbLt crystal structure. Otherwise, the Zn2+ sites have no relation with those observed in Cu/Zn SODs. Our peroxidase assays with guaiacol confirm the POD activity and the effect of the zinc ions for HbGp. Our present results on HbGp metal content and their stability effects is the first step to understand the role of these cations in HbGp function in the future.
      Graphical abstract image

      PubDate: 2016-05-09T06:06:59Z
       
  • Surface complex of ZnTMPyP4 metalloporphyrin with double-stranded
           poly(a)-poly(U)
    • Abstract: Publication date: Available online 6 May 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): G. Tolstykh, V. Sizov, A. Kudrev
      This communication presents synthesis and spectral characterization of metalloporphyrin [Zn(X)TMPyP4] (TMPyP4 is 5,10,15,20-tetrakis (N-methylpyridinium-4-yl)porphyrin), and studies its binding onto anionic surface sites of synthetic double stranded polynucleotide Poly(A)-Poly(U). [Zn(X)TMPyP4] binding with Poly(A)-Poly(U) was monitored by UV–Vis absorbance spectroscopy, two fluorescence spectroscopies and 1H NMR in a working aqueous medium of 0.15M ionic strength, pH7.0 and at 25°C. The evidence provided by spectroscopic measurements and multivariate data analysis suggests the use of this metalloporphyrin as a probe for investigation of the polynucleotide surface. In contrast to TMPyP4 intercalation, an outside adsorption of [Zn(X)TMPyP4] induces an attenuation of luminescence intensity and has little influence on the shape of luminescence band. Special attention was paid to the quantitative description of the interaction between neighboring ligands on the Poly(A)-Poly(U) surface. The intrinsic binding constant to an isolated binding site lgKin 5.8±0.1, the cooperativity parameter ω 1.8±0.2, and number of monomers occupied by a ligand n =2 (25°C; pH7.0) were calculated based upon the recently proposed non-linear least-squares fitting procedure. The discovered cooperativity of binding of [Zn(X)TMPyP4] metalloporphyrin to Poly(A)-Poly(U) is significantly lower as compared to free porphyrin TMPyP4, reflecting minimal mutual influence between the nearest neighboring ligands bound with functional PO4 − groups of the polynucleotide surface.
      Graphical abstract image

      PubDate: 2016-05-09T06:06:59Z
       
  • Effects of Cu(II) and cisplatin on the stability of Specific protein 1
           (Sp1)-DNA binding: Insights into the regulation of copper homeostasis and
           platinum drug transport
    • Abstract: Publication date: Available online 27 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Dong Yan, Isamu Aiba, Helen H.W. Chen, Macus Tien Kuo
      The human high-affinity copper transporter 1 (hCtr1) transports both Cu(I) and cisplatin (cDDP). Because Cu deficiency is lethal yet Cu overload is poisonous, hCtr1 expression is transcriptionally upregulated in response to Cu deficiency but is downregulated under Cu replete conditions in controlling Cu homeostasis. The up- and down-regulation of hCtr1 is regulated by Specific protein 1 (Sp1), which itself is also correspondingly regulated under these Cu conditions. hCtr1 expression is also upregulated by cDDP via upregulation of Sp1. The underlying mechanisms of these regulations are unknown. Using gel-electrophoretic mobility shift assays, we demonstrated here that Sp1-DNA binding affinity is reduced under Cu replete conditions but increased under reduced Cu conditions. Similarly, Sp1-DNA binding affinity is increased by cDDP treatment. This in vitro system demonstrated, for the first time, that regulation of Sp1/hCtr1 expression by these agents is modulated by the stability of Sp1-DNA binding, the first step in the Sp1-mediated transcriptional regulation process.
      Graphical abstract image

      PubDate: 2016-04-30T05:54:03Z
       
  • Cytotoxic trans-platinum(II) complex with 3-hydroxymethylpyridine:
           Synthesis, X-ray structure and biological activity evaluation
    • Abstract: Publication date: Available online 26 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Sabina Grabner, Barbara Modec, Nataša Bukovec, Peter Bukovec, Maja Čemažar, Simona Kranjc, Gregor Serša, Janez Sčančar
      To assess the potential cytostatic properties of Pt(II) complexes with 3-hydroxymethylpyridine (3-hmpy) as the only carrier ligand, novel cis-[PtCl2(3-hmpy)2] (1) and trans-[PtCl2(3-hmpy)2] (2) have been prepared. Elemental analysis, FTIR spectroscopy, multinuclear NMR spectroscopy and X-ray crystallography were used to determine their structures. Based on the results obtained with 3-(4.5-dimethylthiazol-2-yl)-2.5-diphenyl-tetrazolium bromide (MTT) assay and clonogenic assay on T24 human bladder carcinoma cells (T24), the most potent compound 2 was further tested for cytotoxicity in human ovarian carcinoma cell lines - cisplatin sensitive (IGROV 1) and its resistant subclone (IGROV 1/RDDP). The cytotoxicity of compound 2 in IGROV 1/RDDP is comparable to cisplatin. Furthermore, compound 2 induced severe conformational changes in plasmid DNA, which resulted in a delayed onset of apoptosis in T24 cells, and higher amounts of Pt in tumours and serum compared to cisplatin. In addition, in vivo antitumour effectiveness was comparable to that of cisplatin with a smaller reduction of animals' body weight, thus demonstrating that it is a promising transplatin analogue which deserves further studies.
      Graphical abstract image

      PubDate: 2016-04-30T05:54:03Z
       
  • A combined crystallographic analysis and ab initio calculations to
           interpret the reactivity of functionalized hexavanadates and their
           inhibitor potency toward Na+/K+-ATPase
    • Abstract: Publication date: Available online 27 April 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Xiao Xu, Nada Bošnjaković-Pavlović, Mirjana B. Čolović, Danijela Z. Krstić, Vesna M. Vasić, Jean-Michel Gillet, Pingfan Wu, Yongge Wei, Anne Spasojević-de Biré
      In vitro influence of five synthesized functionalized hexavanadates (V6) on commercial porcine cerebral cortex Na+/K+-ATPase activity has been studied. Dose dependent Na+/K+-ATPase inhibition was obtained for all investigated compounds. Calculated half maximal inhibitory concentration IC50 values, in mol/L, for Na+/K+-ATPase were 7.6×10−5, 1.8×10−5, 2.9×10−5, 5.5×10−5 for functionalized hexavanadates (V6) with tetrabutylammonium (TBA) [V6–CH3][TBA]2, [V6–NO2][TBA]2, [V6–OH][TBA]2 and [V6–C3][TBA]2 respectively. [V6–OH][Na]2 inhibited Na+/K+-ATPase activity up to 30% at maximal investigated concentration 1×10−3 mol/L. This reactivity has been interpreted using a study of the non-covalent interactions of functionalized hexavanadate hybrids through Cambridge Structural Database (CSD) analysis. Bibliographic searching has led to 18 different structures and 99 contacts. We have observed that C–H⋯O contacts consolidate the structures. We have also performed density functional theory (DFT) calculations and have determined electrostatic potential values at the molecular surface on a series of functionalized V6. These results enlightened their chemical reactivity and their potential biological applications such as the inhibition of the ATPase.
      Graphical abstract image

      PubDate: 2016-04-30T05:54:03Z
       
  • 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.
      Graphical abstract image

      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.
      Graphical abstract image

      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.
      Graphical abstract image

      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.
      Graphical abstract image

      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

      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
       
  • 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.
      Graphical abstract image

      PubDate: 2016-04-18T05:15:13Z
       
  • 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.
      Graphical abstract image

      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.
      Graphical abstract image

      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.
      Graphical abstract image

      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.
      Graphical abstract image

      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.
      Graphical abstract image

      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.
      Graphical abstract image

      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.
      Graphical abstract image

      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).
      Graphical abstract image

      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.
      Graphical abstract image

      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.
      Graphical abstract image

      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.
      Graphical abstract image

      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
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2015