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  Subjects -> CHEMISTRY (Total: 848 journals)
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INORGANIC CHEMISTRY (41 journals)

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Acta Polymerica     Hybrid Journal   (Followers: 7)
Additives for Polymers     Full-text available via subscription   (Followers: 20)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Polymer Technology     Hybrid Journal   (Followers: 12)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 3)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 8)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 1)
Current Methods in Inorganic Chemistry     Full-text available via subscription   (Followers: 1)
European Journal of Inorganic Chemistry     Hybrid Journal   (Followers: 7)
European Polymer Journal     Hybrid Journal   (Followers: 40)
Heterocyclic Communications     Hybrid Journal  
High Performance Polymers     Hybrid Journal  
Indian Journal of Chemistry - Section A     Open Access   (Followers: 7)
Inorganic Chemistry     Full-text available via subscription   (Followers: 20)
Inorganic Chemistry Communications     Hybrid Journal   (Followers: 9)
Inorganic Chemistry Frontiers     Full-text available via subscription   (Followers: 1)
Inorganic Materials     Hybrid Journal   (Followers: 3)
Inorganic Materials: Applied Research     Hybrid Journal   (Followers: 1)
Inorganica Chimica Acta     Hybrid Journal   (Followers: 5)
Inorganics     Open Access  
International Journal of Bio-Inorganic Hybrid Nanomaterials     Open Access   (Followers: 1)
International Journal of Inorganic Chemistry     Open Access   (Followers: 2)
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 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: 0.983]   [H-I: 100]   [3 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0162-0134
   Published by Elsevier Homepage  [3039 journals]
  • Copper (II) and zinc (II) complexes with flavanone derivatives:
           Identification of potential cholinesterase inhibitors by on-flow assays
    • Abstract: Publication date: Available online 17 September 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): André Lucio Franceschini Sarria, Adriana Ferreira Lopes Vilela, Bárbara Mammana Frugeri, João Batista Fernandes, Rose Maria Carlos, Maria Fátima das Graças Fernandes da Silva, Quezia Bezerra Cass, Carmen Lúcia Cardoso
      Metal chelates strongly influence the nature and magnitude of pharmacological activities in flavonoids. In recent years, studies have shown that a promising class of flavanone–metal ion complexes can act as selective cholinesterase inhibitors (ChEIs), which has led our group to synthesize a new series of flavanone derivatives (hesperidin, hesperetin, naringin, and naringenin) complexed to either copper (II) or zinc (II) and to evaluate their potential use as selective ChEIs. Most of the synthesized complexes exhibited greater inhibitory activity against acetylcholinesterase (AChE) than against butyrylcholinesterase (BChE). Nine of these complexes constituted potent, reversible, and selective ChEIs with inhibitory potency (IC50) and inhibitory constant (Ki) ranging from 0.02 to 4.5μM. Copper complexes with flavanone-bipyridine derivatives afforded the best inhibitory activity against AChE and BChE. The complex Cu(naringin)(2,2′-bipyridine) (11) gave IC50 and Ki values of 0.012±0.002 and 0.07±0.01μM for huAChE, respectively, which were lower than the inhibitory values obtained for standard galanthamine (IC50 =206±30.0 and Ki =126±18.0μM). Evaluation of the inhibitory activity of this complex against butyrylcholinesterase from human serum (huBChE) gave IC50 and Ki values of 8.0±1.4 and 2.0±0.1μM, respectively. A Liquid Chromatography-Immobilized Capillary Enzyme Reactor by UV detection (LC-ICER-UV) assay allowed us to determine the IC50 and Ki values and the type of mechanism for the best inhibitors.
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      PubDate: 2016-09-21T23:24:52Z
       
  • Effects of metal ions and cosolutes on G-quadruplex topology
    • Abstract: Publication date: Available online 14 September 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Taiga Fujii, Peter Podbevšek, Janez Plavec, Naoki Sugimoto
      Topologies of G-quadruplexes depend on oligonucleotide sequences and on environmental factors, and the diversity of G-quadruplex topologies complicates investigation of functions of these nucleic acid structures. To investigate how metal ions and cosolutes regulate topologies of G-quadruplexes, we stabilized the antiparallel conformation by insertion of 2′-deoxyxanthosine and 8-oxo-2′-deoxyguanosine into selected positions of an oligonucleotide. Thermodynamic analyses of the oligonucleotide revealed that Na+ stabilized the antiparallel G-quadruplex, whereas K+ destabilized this topology. This result suggests that metal ions selectively stabilize G-quadruplex topologies with cavities between G-quartet planes of certain sizes. In the presence of KCl in 20wt% poly(ethylene glycol) with average molecular weight of 200, the antiparallel basket-type G-quadruplex conformation was not stabilized compared with the dilute condition. In the presence of NaCl, the cosolute did stabilize the G-quadruplex with respect to the dilute condition. The presented data show that metal ions and cosolutes regulate topologies of G-quadruplexes through mechanisms that depend on sizes of metal ion cavities and hydration states.
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      PubDate: 2016-09-16T22:56:20Z
       
  • Role of subcellular calcium redistribution in regulating apoptosis and
           autophagy in cadmium-exposed primary rat proximal tubular cells
    • Abstract: Publication date: Available online 14 September 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Fei Liu, Zi-Fa Li, Zhen-Yong Wang, Lin Wang
      Ca2+ signaling plays a vital role in regulating apoptosis and autophagy. We previously proved that cytosolic Ca2+ overload is involved in cadmium (Cd)-induced apoptosis in rat proximal tubular (rPT) cells, but the source of elevated cytosolic Ca2+ concentration ([Ca2+]c) and the effect of potential subcellular Ca2+ redistribution on apoptosis and autophagy remain to be elucidated. Firstly, data showed that Cd-induced elevation of [Ca2+]c was primarily generated intracellularly. Moreover, elevations of [Ca2+]c and mitochondrial Ca2+ concentration ([Ca2+]mit) with depletion of endoplasmic reticulum (ER) Ca2+ levels ([Ca2+]ER) were revealed in Cd-treated rPT cells, but this subcellular Ca2+ redistribution was significantly suppressed by 2-Aminoethoxydiphenyl borate (2-APB). Elevated inositol 1,4,5-trisphosphate (IP3) levels with up-regulated IP3 receptor (IP3R) protein levels were shown in Cd-exposed cells, confirming that IP3R-mediated ER Ca2+ release results in the elevation of [Ca2+]c. Up-regulated sequestosome 1 (p62) protein levels and autophagic flux assay demonstrated that Cd impaired autophagic degradation, while N-acetylcysteine (NAC) markedly attenuated Cd-induced p62 and microtubule-associated protein 1 light chain 3-II (LC3-II) accumulation, implying that the inhibition of autophagic flux was due to oxidative stress. Furthermore, pharmacological modulation of [Ca2+]c with 1,2-Bis (2-aminophenoxy) ethane-N,N,N′,N′-tetraacetic acid acetoxymethyl ester (BAPTA-AM) and 2-APB alleviated Cd-mediated apoptosis, inhibition of autophagic degradation and subsequent cytotoxicity, while thapsigargin (TG) had the opposite regulatory effect on them. In summary, cytosolic calcium overload originated from IP3R-mediated ER Ca2+ release has a negative impact on Cd nephrotoxicity through its promotion of apoptosis and inhibition of autophagic flux.
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      PubDate: 2016-09-16T22:56:20Z
       
  • Synthesis and biological evaluation of PEGylated CuO nanoparticles
    • Abstract: Publication date: Available online 14 September 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): K. Giannousi, E. Hatzivassiliou, S. Mourdikoudis, G. Vourlias, A. Pantazaki, C. Dendrinou-Samara
      There is a growing field of research into the physicochemical properties of metal oxide nanoparticles (NPs) and their potential use against tumor formation, development and progression. Coated NPs with biocompatible surfactants can be incorporated into the natural metabolic pathway of the body and specifically favor delivery to the targeted cancerous cells versus normal cells. Polyethylene glycol (PEG) is an FDA approved, biocompatible synthetic polymer and PEGylated NPs are regarded as “stealth” nanoparticles, which are not recognized by the immune system. Herein, PEGylated cupric oxide nanoparticles (CuO NPs) with either PEG 1000 or PEG 8000 were hydrothermally prepared upon properly adjusting the reaction conditions. Depending on the reaction time CuO NPs in the range of core sizes 11–20nm were formed, while hydrodynamic sizes substantially varied (330–1120nm) with improved colloidal stability in PBS. The anticancer activity of the NPs was evaluated on human cervical carcinoma HeLa cells by using human immortalized embryonic kidney 293 FT cells as a control. Viability assays (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, MTT) revealed that CuO NPs could selectively reduce viability of tumor cells (IC50 values 11.91–25.78μg/mL). Reactive oxygen species (ROS) production, cell membrane damage and apoptotic DNA laddering were also evident by nitroblue tetrazolium (NBT) reduction, lactate dehydrogenase (LDH) release assays and DNA electrophoresis, respectively. CuO NPs strongly inhibited lipoxygenase (LOX) enzymatic activity with IC50 values 4–5.9μg/mL, highlighting in that manner their anti-inflammatory activity.
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      PubDate: 2016-09-16T22:56:20Z
       
  • Chemical properties and biotoxicity of several chromium picolinate
           derivatives
    • Abstract: Publication date: Available online 14 September 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Bin Liu, Yanfei Liu, Jie Chai, Xiangquan Hu, Duoming Wu, Binsheng Yang
      As a man-made additive, chromium picolinate Cr(pic)3 has become a popular dietary supplement worldwide. In this paper Cr(pic)3 and its new derivatives Cr(6-CH3-pic)3 (1), [Cr(6-NH2-pic)2(H2O)2]NO3 (2) and Cr(3-NH2-pic)3 (3) were synthesized, and complexes 1 and 2 were characterized by X-ray crystal structure (where pic=2-carboxypyridine). The relationship between the chemical properties and biotoxicity of these complexes was fully discussed: (1) The dynamics stability of chromium picolinate complexes mainly depends on the CrN bonds length. (2) There is a positive correlation between the dynamics stability, electrochemical potentials and generation of reactive oxygen species through Fenton-like reaction. (3) However, no biological toxicity was observed through MTT and sub-chronic oral toxicity study for these chromium picolinate compounds. Together, our findings establish a framework for understanding the structure-property-toxicity relationships of the chromium picolinate complexes.
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      PubDate: 2016-09-16T22:56:20Z
       
  • Ru(III) anticancer agents with aromatic and non-aromatic dithiocarbamates
           as ligands: Loading into PF127 micelles and preliminary biological studies
           
    • Abstract: Publication date: Available online 14 September 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): S. Scintilla, L. Brustolin, A. Gambalunga, F. Chiara, A. Trevisan, C. Nardon, D. Fregona
      Since the discovery of cisplatin in the 1960s, other metal complexes have been investigated as potential antitumor agents to overcome the side-effects associated with the administration of the Pt-based drug. In line with our previous research, in this work we report the synthesis and characterization of mono- and dinuclear Ru(III) complexes with the pyrrolidinedithiocarbamate (PDT) ligand and the more sterically-hindered carbazole-dithiocarbamato ligand (CDT), to compare their properties (both at the chemical and antiproliferative level), in an attempt to assess a structure-activity rationale. Moreover, to overcome the scarce solubility under physiological conditions of the Ru(III)-dithiocarbamato compounds, the biocompatible copolymer Pluronic® F127 has been used, to encapsulate the metal derivatives in water-soluble micellar carriers. Finally, preliminary biological evaluations on CDT and PDT compounds along with their nanoformulations, open intriguing perspectives in anticancer chemotherapy. In particular, comparing the structure of the Ru(III) derivatives, the ionic dinuclear PDT complex shows an important cytotoxic action in comparison to its neutral counterparts. Moreover, the micellar carrier improves the overall activity of the encapsulated Ru(III)-PDT chemotherapeutics. On the other hand, the nanoformulation of the CDT derivatives allows us to solubilize both the 1:3 and the 2:5 complexes and to state their inactivity.
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      PubDate: 2016-09-16T22:56:20Z
       
  • Novel mononuclear Pt2+ and Pd2+ complexes containing
           (2,3-f)pyrazino(1,10)phenanthroline-2,3-dicarboxylic acid as a multi-donor
           ligand. Synthesis, structure, interaction with DNA, in vitro cytotoxicity,
           and apoptosis
    • Abstract: Publication date: Available online 14 September 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Ya-guang Sun, Yi-ning Sun, Li-xin You, Yi-nan Liu, Fu Ding, Bao-yi Ren, Gang Xiong, Valerian Dragutan, Ileana Dragutan
      New cytotoxic, mononuclear Pt and Pd coordination complexes featuring the planar, multi-donor ligand (2,3-f)pyrazino(1,10)phenanthroline-2,3-dicarboxylic acid (H2PPDA) have been synthesized under hydrothermal conditions (in water, at high temperature and pressure) and fully characterized. The complexes were proven to be isostructural by applying the single-crystal X-ray diffraction technique. UV–Vis and fluorescence spectroscopy investigations on their interaction with fish sperm DNA revealed a considerable binding capacity while gel electrophoresis provided evidence in favor of cleavage of pBR322 plasmid DNA. The newly synthesized complexes manifested significant in vitro cytotoxic activity against two different human cancer cell lines, the KB and JEKO cells, with cell death mainly caused by apoptosis.
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      PubDate: 2016-09-16T22:56:20Z
       
  • Ru(II) complexes bearing guanidinium ligands as potent anticancer agents
    • Abstract: Publication date: Available online 14 September 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Wen-Xiu Chen, Xing-Dong Song, Shu-Fen He, Jing Sun, Jia-Xi Chen, Tie Wu, Zong-Wan Mao
      Two ruthenium(II) complexes containing guanidinium ligands have been synthesized and characterized for the first time. It was found that the two complexes exhibit moderate antitumor activity in Hela, A549, CNE-2, MCF-7, and HepG2 human tumor cells. Flow cytometric analysis showed that both complexes arrested the cell cycle in the G2/M phase and induced apoptosis in Hela cells. Mechanism studies indicate that both complexes induced apoptosis through caspase- and reactive oxygen species (ROS)-dependent pathways. Additionally, the two complexes displayed higher phototoxicity to tumor cells and almost no influence on normal liver LO2 cells upon irradiation at 450nm.
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      PubDate: 2016-09-16T22:56:20Z
       
  • Complicated function of dopamine in Aβ-related neurotoxicity: Dual
           interactions with Tyr10 and SNK(26–28) of Aβ
    • Abstract: Publication date: Available online 14 September 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Mengmeng Liu, Lu Kou, Yannan Bin, Liping Wan, Juan Xiang
      With the capability to inhibit the formation of amyloid β peptides (Aβ) fibril, dopamine (DA) and other catechol derivatives have been considered for the potential treatment of Alzheimer's disease (AD). Such treatment, however, remains debatable because of the diverse functions of Aβ and DA in AD pathology. Moreover, the complicated oxidation accompanying DA has caused the majority of the previous research to focus on the binding of DA oxides onto Aβ. The molecular mechanism by which Aβ interacts with the reduction state of DA, which is correlative with the brain function, should be urgently explored. By controlling rigorous anaerobic experimental conditions, this work investigated the molecular mechanism of the Aβ/DA interaction, and two binding sites were revealed. For the binding of DA, Tyrosine (Tyr10) was identified as the strong binding site, and serine-asparagine-lysing (SNK(26–28)) segment was the weak binding segment. Furthermore, the Thioflavin T (THT) fluorescence confirmed DA's positive function of inhibiting Aβ aggregation through its weakly binding with SNK(26–28) segment. Meanwhile, 7-OHCCA fluorescence exhibited DA's negative function of enhancing OH generation through inhibiting the Aβ/Cu2+ coordination. The viability tests of the neuroblastoma SH-SY5Y cells displayed that the coexistence of DA, Cu2+, and Aβ induced lower cell viability than free Cu2+, indicating the significant negative effect of excessive DA on AD progression. This research revealed the potential DA-induced damage in AD brain, which is significant for understanding the function of DA in AD neuropathology and for designing a DA-related therapeutic strategy for AD.
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      PubDate: 2016-09-16T22:56:20Z
       
  • Manganese binding to antioxidant peptides involved in extreme radiation
           resistance in Deinococcus radiodurans
    • Abstract: Publication date: Available online 30 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Massimiliano Peana, Serenella Medici, Heather A. Pangburn, Thomas J. Lamkin, Malgorzata Ostrowska, Elzbieta Gumienna-Kontecka, Maria Antonietta Zoroddu
      A decapeptide, DEHGTAVMLK (DP1), and its random scrambled version, THMVLAKGED (DP2), have been studied for their interactions with manganese. The amino acid composition of the peptides was selected to include the majority of the most prevalent amino acids present in a Deinococcus radiodurans bacterium cell-free extract that contains components capable of conferring extreme resistance to ionizing radiation. The extract appears to be rich in Mn(II) complexes which seem to be responsible for protecting proteins from Reactive Oxygen Species damage. We focused our attention on the interaction of the decapeptides with Mn(II) ion with the aim of obtaining information on the possible complexes formed, by using NMR, EPR, and ESI-MS techniques.
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      PubDate: 2016-09-02T22:10:46Z
       
  • Volumetric analysis of formation of the complex of G-quadruplex DNA with
           hemin using high pressure
    • Abstract: Publication date: Available online 2 September 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Shuntaro Takahashi, Sudipta Bhowmik, Naoki Sugimoto
      DNA guanine-quadruplexes (G-quadruplexes) complexed with the Fe-containing porphyrin, hemin (iron(III)-protoporphyrin IX), can catalyze oxidation reactions. This so-called DNAzyme has been widely used in the field of DNA nanotechnology. To improve DNAzyme properties, we sought to elucidate the interaction mechanism between G-quadruplex DNA and hemin. Here, we performed volumetric analyses of formation of the complex between an oligonucleotide with the sequence of human telomeric DNA (h-telo) and hemin. The G-quadruplex DNA alone and the G-quadruplex DNA-hemin complex were destabilized with increasing pressure in Na+ buffer. The pressure required to destabilize the h-telo-hemin complex was less in K+-containing buffer than in buffer with Na+, which indicates that there was a smaller volumetric change upon h-telo formation in K+ buffer than in Na+ buffer. The calculated change in h-telo-hemin binding volume (∆ V b) in the Na+ buffer was 2.5mLmol−1, whereas it was −41.7 in mL mol−1 the K+ buffer. The DNAzyme activity in the K+ buffer was higher than that in the Na+ buffer at atmospheric pressure. Interestingly, the pressure effect on the destabilization of the h-telo-hemin complex in the presence of poly(ethylene glycol)200 (PEG200) was repressed compared to that in the absence of PEG200. These results suggest that differences in volumetric parameters reflect different mechanisms of interaction between hemin and h-telo due to differences in both the fit of hemin into the h-telo structure and hydration. Thus, the pressure-based thermodynamic analysis provided important information about complex formation and could be a useful index to improve function of DNAzymes.
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      PubDate: 2016-09-02T22:10:46Z
       
  • Influence of the N-terminus acetylation of Semax, a synthetic analog of
           ACTH(4-10), on copper(II) and zinc(II) coordination and biological
           properties
    • Abstract: Publication date: Available online 27 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Antonio Magrì, Giovanni Tabbì, Alessandro Giuffrida, Giuseppe Pappalardo, Cristina Satriano, Irina Naletova, Vincenzo G. Nicoletti, Francesco Attanasio
      Semax is a heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) that encompasses the sequence 4-7 of N-terminal domain of the adrenocorticotropic hormone and a C-terminal Pro-Gly-Pro tripeptide. N-terminal amino group acetylation (Ac-Semax) modulates the chemical and biological properties of parental peptide, modifying the ability of Semax to form complex species with Cu(II) ion. At physiological pH, the main complex species formed by Ac-Semax, [CuLH−2]2−, consists in a distorted CuN3O chromophore with a weak apical interaction of the methionine sulphur. Such a complex differs from the Cu(II)-Semax complex system, which exhibits a CuN4 chromophore. The reduced ligand field affects the [CuLH−2]2− formal redox potential, which is more positive than that of Cu(II)-Semax corresponding species. In the amino-free form, the resulting complex species is redox-stable and unreactive against ascorbic acid, unlike the acetylated form. Semax acetylation did not protect from Cu(II) induced toxicity on a SH-SY5Y neuroblastoma cell line, thus demonstrating the crucial role played by the free NH2 terminus in the cell protection. Since several brain diseases are associated either to Cu(II) or Zn(II) dyshomeostasis, here we characterized also the complex species formed by Zn(II) with Semax and Ac-Semax. Both peptides were able to form Zn(II) complex species with comparable strength. Confocal microscopy imaging confirmed that peptide group acetylation does not affect the Zn(II) influx in neuroblastoma cells. Moreover, a punctuate distribution of Zn(II) within the cells suggests a preferred subcellular localization that might explain the zinc toxic effect. A future perspective can be the use of Ac-Semax as ionophore in antibody drug conjugates to produce a dysmetallostasis in tumor cells.
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      PubDate: 2016-08-30T11:24:13Z
       
  • Synthesis, characterization, and binding affinity of hydrosulfide
           complexes of synthetic iron(II) prphyrinates
    • Abstract: Publication date: Available online 27 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Daniel J. Meininger, Hadi D. Arman, Zachary J. Tonzetich
      The binding and reactivity of the hydrosulfide ion (HS−) to iron(II) porphyrinates has been examined for several synthetic meso-tetraphenylporphine (TPP) derivatives. In all cases, HS− coordinates to the iron centers in a 1:1 stoichiometry with formation constants (K f) that reflect the electronic characteristics of the porphyrinate ligands. In the case of the F8TPP ligand (F8TPP=dianion of 5,10,15,20-tetrakis(2,6-difluorophenyl)porphine), an intermediate complex proposed as the hydrosulfide bridged dimer, (Bu4N)[Fe2(μ-SH)(F8TPP)2], was identified by NMR spectroscopy en route to formation of (Bu4N)[Fe(SH)(F8TPP)]. A robust procedure is reported for the synthesis and isolation of the parent hydrosulfide adduct, (Bu4N)[Fe(SH)(TPP)], which has permitted a detailed examination of its spectroscopy and chemical reactivity. Electrochemical measurements demonstrate that [Fe(SH)(TPP)]− is oxidized reversibly at a potential of −0.832V (vs ferrocene/ferrocenium) consistent with other iron porphyrinates containing sulfur-based ligands. Despite this fact, chemical oxidation of (Bu4N)[Fe(SH)(TPP)] with ferrocenium tetrafluoroborate produced only [Fe(TPP)] indicating that the putative iron(III) hydrosulfide adduct, [Fe(SH)(TPP)], decomposes rapidly. Treatment of (Bu4N)[Fe(SH)(TPP)] with other biologically relevant molecules such as NO and 1,2-dimethylimidazole resulted in simple displacement of the HS− ligand as governed by the relative K f values of the added ligands. The solid-state structure of one hydrosulfide adduct, (Bu4N)[Fe(SH)(F8TPP)], was determined by X-ray crystallography and found to display the expected five-coordinate geometry about iron with an Fe-S distance of 2.323(1) Å. The relevance of the hydrosulfide chemistry with synthetic iron porphyrinates is discussed in terms of the possible reactivity for H2S and its derivatives at heme sites in biology.
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      PubDate: 2016-08-30T11:24:13Z
       
  • Crucial residue Trp158 of lipoprotein PiaA stabilizes the ferrichrome-PiaA
           complex in Streptococcus pneumoniae
    • Abstract: Publication date: Available online 27 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Liang Zhang, Nan Li, Kun Cao, Xiao-Yan Yang, Guandi Zeng, Xuesong Sun, Qing-Yu He
      The pathogenic Streptococcus pneumoniae (S. pneumoniae) has evolved a special mechanism such as pneumococcal iron acquisition ATP binding cassette (PiaABC)to take up siderophore-iron from its host. The cell-surface lipoprotein PiaA, a key component of PiaABC, is the primary receptor to bind ferrichrome (Fc). To study the structure-function relationship of PiaA, three conservative amino-acid residues, Trp63, Trp158 and Phe255, in the hydrophobic barrel of the metal binding site of PiaA, were individually and collectively mutated to alanine; and the resulted single-point mutants, W63A, W158A and F255A, and triple mutant W63A/W158A/F255A were characterized by using biochemical and biophysical methods. Experiments showed that wild-type PiaA (WT-PiaA) and the single-point mutant proteins bound Fc with a similar kinetics mode, but the reaction rate of W158A was lower than that for WT-PiaA. The binding affinity of W158A toward Fc was significantly weaker than that of the WT-PiaA-Fc (wild-type PiaA bound with Fc)interaction. Furthermore, the absence of Trp158 in the protein led to a significant impact on the secondary structure of PiaA, resulting in a labile conformational structure of W158A, with impaired resistance to thermal and chemical denaturation. Collectively, Trp158 is a crucial residue for binding Fc, playing an important role in stabilizing the PiaA-Fc complex. This study revealed the critical role of the conserved tryptophan residues in Fc-binding protein PiaA, and provided valuable information for understanding the Fc transport mechanism mediated by PiaA or its homologous proteins in bacteria.
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      PubDate: 2016-08-30T11:24:13Z
       
  • Globin domain interactions control heme pocket conformation and
           oligomerization of globin coupled sensors
    • Abstract: Publication date: Available online 27 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Shannon Rivera, Justin L. Burns, Gregory E. Vansuch, Bryant Chica, Emily E. Weinert
      Globin coupled sensors (GCS) are O2-sensing proteins used by bacteria to monitor the surrounding gaseous environment. To investigate the biphasic O2 dissociation kinetics observed for full-length GCS proteins, isolated globin domains from Pectobacterium carotovorum ssp. carotovorum (PccGlobin), and Bordetella pertussis (BpeGlobin), have been characterized. PccGlobin is found to be dimeric, while BpeGlobin is monomeric, indicating key differences in the globin domain dimer interface. Through characterization of wild type globin domains and globin variants with mutations at the dimer interface and within the distal pocket, dimerization of the globin domain is demonstrated to correlate with biphasic dissociation kinetics. Furthermore, a distal pocket tyrosine is identified as the primary hydrogen bond donor, while a secondary hydrogen bond donor within the distal heme pocket is involved in conformation(s) that lead to the second O2 dissociation rate. These findings highlight the role of the globin dimer interface in controlling properties of both the heme pocket and full-length GCS proteins.
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      PubDate: 2016-08-30T11:24:13Z
       
  • Controlled coordination in vanadium(V) dimethylhydrazido compounds
    • Abstract: Publication date: Available online 29 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Takashi Sakuramoto, Toshiyuki Moriuchi, Toshikazu Hirao
      The vanadium(V) dimethylhydrazido compounds were structurally characterized to elucidate the effect of the alkoxide ligands in the coordination environment of vanadium(V) hydrazido center. The single-crystal X-ray structure determination of the vanadium(V) dimethylhydrazido compound with isopropoxide ligands revealed a dimeric structure with the V(1)-N(1) distance of 1.680(5)Å, in which each vanadium atom is coordinated in a distorted trigonal-bipyramidal geometry (τ5 =0.81) with the hydrazido and bridging isopropoxide ligands in the apical positions. On the contrary, nearly tetrahedral arrangement around the vanadium metal center (τ4 =0.06) with the V(1)-N(1) distance of 1.660(2)Å was observed in the vanadium(V) dimethylhydrazido compound with tert-butoxide ligands. The introduction of the 2,2′,2″-nitrilotriethoxide ligand led to a pseudo-trigonal-bipyramidal geometry (τ5 =0.92) at the vanadium center with the V(1)-N(1) distance of 1.691(5)Å, wherein vanadium atom is pulled out of the plane formed by the nitrilotriethoxide oxygen atoms in the direction of the hydrazido nitrogen. The coordination from the apical ligand in the vanadium(V) dimethylhydrazido compound was found to result in the longer V(1)-N(1) distance.
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      PubDate: 2016-08-30T11:24:13Z
       
  • In vitro and in vivo antitumor activity of a novel carbonyl ruthenium
           compound, the
           ct-[RuCl(CO)(dppb)(bipy)]PF­6[dppb=1,4-bis(disphenylphosphine)butane and
           bipy=2,2'-bipyridine]
    • Abstract: Publication date: Available online 25 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Andréa P. Carnizello, Marília I.F. Barbosa, Monize Martins, Natália H. Ferreira, Pollyanna F. Oliveira, Geórgia M. Magalhães, Alzir A. Batista, Denise C. Tavares
      This study performed in vitro and in vivo biological assays of the ruthenium (II) compound ct-[RuCl(CO)(dppb)(bipy)]PF6 (where, dppb =1.4-bis(diphenylphosphine)butane and bipy =2.2′-bipyridine). The cytotoxic activity of this compound was evaluated against different tumor cell lines (HeLa, human cervical adenocarcinoma; MCF7, human breast adenocarcinoma; MO59J, human glioblastoma; HepG2, hepatocellular carcinoma and B16F10, murine melanoma) and healthy cell line (V79, Chinese hamster lung fibroblasts), by XTT (sodium 2,3′-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)-carbonyl]-3,4-tetrazolium]-bis(4-methoxy-6-nitro)benzene-sulfonic acid hydrate) method. A syngeneic murine melanoma tumor model (B16F10) was used to evaluate its antitumor activity. Additionally, experiments were performed to assess the interactions with ctDNA (calf thymus DNA) and BSA (bovine serum albumin). The results showed that ct-[RuCl(CO)(dppb)(bipy)]PF6 was cytotoxic against all tumor cell lines tested. Furthermore, the compound was more effective against tumor cells compared to the normal cell line, indicating selectivity, especially in B16F10 cells. Significant tumor growth reduction was observed in animals treated with the compound compared to the untreated control. Histopathological analysis of tumor tissue revealed a significant reduction of mitosis in animals treated with the compound compared to the untreated control. In the ctDNA and BSA interaction experiments, the compound in study showed weak interactions with ctDNA and hydrophobic interactions with BSA. The ruthenium compound investigated showed promising results in in vitro and in vivo biological assays.
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      PubDate: 2016-08-26T11:07:05Z
       
  • In Situ Synthesis of High Swell Ratio Polyacrylic Acid/Silver
           Nanocomposite Hydrogels and Their Antimicrobial Properties
    • Abstract: Publication date: Available online 24 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Yi-Syuan Wei, Ko-Shao Chen, Lii-Tzu Wu
      Silver nanocomposites embedded within a polymer matrix have attracted attention in recent years. Ionic polymer hydrogels comprise networks of chemically or physically cross-linked polymers that swell considerably in an appropriate solvent. In this study, we used a solution of the carboxylic monomer acrylic acid and silver nitrate to prepare nanocomposite hydrogels through ultraviolet (UV)-light irradiation. Silver-impregnated biomaterial composed of acrylic acid contains only a monomer and no cross-linker. The formation of hydrogels and reduction of silver nanoparticles were affected by the preparation parameters, that is, the monomer concentration and silver nitrate concentration. The morphology, structure, and size of the silver nanocomposite hydrogels were evaluated through field emission scanning electron microscopy and UV–visible absorption. The antimicrobial activity of the samples was tested against fourstandard strains Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli; and five clinical bacterial isolates Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumonia. The silver nanocomposite hydrogels exhibited an interconnected porous structure and could absorb 400 to 550g of deionized water per gram of dried hydrogel. Moreover, these hydrogels produced a strong antibacterial effect, which can be useful in developing new superabsorbent antimicrobial pharmaceutical products.
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      PubDate: 2016-08-26T11:07:05Z
       
  • The effects of the glycation of transferrin on chromium binding and the
           transport and distribution of chromium In Vivo
    • Abstract: Publication date: Available online 25 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Ge Deng, Samantha L. Dyroff, Molly Lockart, Michael K. Bowman, John B. Vincent
      Chromium (III) has been shown to act as a pharmacological agent improving insulin sensitivity in rodent models of obesity, insulin resistance, and diabetes. To act in beneficial fashion, chromium must reach insulin-sensitive tissues. Chromium is transported from the bloodstream to the tissues by the iron-transport protein transferrin. When blood concentrations of glucose are high (as in a diabetic subject), transferrin can be glycated, modifying its ability to bind and transport iron. However, the effects of glycation of transferrin on its ability to bind and transport Cr have not been examined previously. Storage of transferrin at 37°C in the presence and absence of glucose has significant effects on the binding of Cr. Transferrin stored in the absence of glucose only binds one equivalent of Cr tightly, compared to the normal binding of two equivalents of Cr by transferrin. Glycated transferrin (stored in the presence of glucose) binds two equivalents of Cr but the changes in its extinction coefficient at 245nm that accompany binding suggest that the Cr-bound transferrin possesses a conformation that deviates appreciably from untreated transferrin. These changes have dramatic effects, greatly reducing the ability of transferrin to transport Cr in vivo in rats. The results suggest that glycation of transferrin in subjects with high blood glucose concentrations should reduce the ability of Cr from pharmacological agents to enter tissues.
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      PubDate: 2016-08-26T11:07:05Z
       
  • The Heme-Based Oxygen Sensor Rhizobium etli FixL: Influence of Auxiliary
           Ligands on Heme Redox Potential and Implications on the Enzyme Activity
    • Abstract: Publication date: Available online 26 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Nathalie Honorio-Felício, Marta S.P. Carepo, Tércio de F. Paulo, Luiz Gonzaga de França Lopes, Eduardo H.S. Sousa, Izaura C.N. Diógenes, Paul V. Bernhardt
      Conformational changes associated to sensing mechanisms of heme-based protein sensors are a key molecular event that seems to modulate not only the protein activity but also the potential of the FeIII/II redox couple of the heme domain. In this work, midpoint potentials (E m) assigned to the FeIII/II redox couple of the heme domain of FixL from Rhizobium etli (ReFixL) in the unliganded and liganded states were determined by spectroelectrochemistry in the presence of inorganic mediators. In comparison to the unliganded ReFixL protein (+19mV), the binding to ligands that switch off the kinase activity induces a negative shift, i. e. E m =−51, −57 and −156mV for O2, imidazole and CN−, respectively. Upon binding to CO, which does not affect the kinase active, E m was observed at +21mV. The potential values observed for FeIII/II of the heme domain of ReFixL upon binding to CO and O2 do not follow the expected trend based on thermodynamics, assuming that positive potential shift would be expected for ligands that bind to and therefore stabilize the FeII state. Our results suggest that the conformational changes that switch off kinase activity upon O2 binding have knock-on effects to the local environment of the heme, such as solvent rearrangement, destabilize the FeII state and counterbalances the FeII-stabilizing influence of the O2 ligand.
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      PubDate: 2016-08-26T11:07:05Z
       
  • Triphenylphosphane Pt(II) complexes containing biologically active natural
           polyphenols: Synthesis, crystal structure, molecular modeling and
           cytotoxic studies
    • Abstract: Publication date: Available online 9 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Maria Michela Dell’Anna, Valentina Censi, Benedetta Carrozzini, Rocco Caliandro, Nunzio Denora, Massimo Franco, Daniele Veclani, Andrea Melchior, Marilena Tolazzi, Piero Mastrorilli
      Platinum complexes bearing phosphane ligands in cis configuration with deprotonated flavonoids (3-hydroxyflavone, quercetin) and deprotonated ethyl gallate were synthesized starting from cis-[PtCl2(PPh3)2]. In all cases, O,O’ chelate structures were obtained. While quercetin and ethyl gallate complexes are quite stable in solution, the 3-hydroxyflavonate complex undergoes a slow aerobic photodegradation in solution with formation of salicylic and benzoic acids. The XRD structures of quercetin and ethyl gallate complexes are reported. Cell cycle studies (in the dark) of the complexes in two human cell lines revealed that the cytotoxic activity of the complex bearing 3-hydroxyflavonate is higher than those exhibited by 3-hydroxyflavone or by cis-[PtCl2(PPh3)2] alone. DFT studies on the hydrolysis pathway for the 3-hydroxyflavone and ethyl gallate complexes explained the different cytotoxic activity observed for the two compounds on the basis of the different intermediates formed during hydrolysis (relatively inert hydroxy Pt complexes for ethyl gallate and monoaqua complexes for 3-hydroxyflavone).
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      PubDate: 2016-08-13T10:11:10Z
       
  • The synergistic antibacterial activity and mechanism of multicomponent
           metal ions-containing aqueous solutions against Staphylococcus aureus
    • Abstract: Publication date: Available online 5 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Xiaolan Wang, Shaoxiang Liu, Mei Li, Peng Yu, Xiao Chu, Lihua Li, Guoxin Tan, Yingjun Wang, Xiaofeng Chen, Yu Zhang, Chengyun Ning
      Silver (Ag+), zinc (Zn2+) and copper (Cu2+) ions, are well known for their broad-spectrum antibacterial activities while generating low resistance. However, whether or multiple metal ions in aqueous solutions acted synergistically or antagonistically antimicrobial properties, remained unknown. Therefore, it was of great significance to investigate the antibacterial properties of multicomponent metal ions-containing aqueous solutions. In this study, the antibacterial activities of multicomponent metal ions-containing aqueous solutions were investigated for the first time. We found that the antibacterial activities of multicomponent metal ions-containing aqueous solutions were higher than those of single metal ion-containing aqueous solution. Furthermore, the synergistic antibacterial mechanism of these multicomponent metal ions-containing aqueous solutions was first investigated. The generation of reactive oxygen species (ROS) through electron transfer in the enzymes and Fenton reactions formed the main synergistic antibacterial mechanism of the multicomponent metal ions-containing aqueous solutions. Therefore, the encouraging results demonstrate the great potential applications of multicomponent metal ions for the design of new biomaterials or prosthesis containing Ag-Cu-Zn alloy which can release Ag+, Zn2+ and Cu2+ and minimize the risk of hospital acquired infection.
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      PubDate: 2016-08-08T09:43:52Z
       
  • Near-infrared luminescence and RNA cleavage ability of lanthanide Schiff
           base complexes derived from
           N,N′-bis(3-methoxysalicylidene)ethylene-1,2-diamine ligands
    • Abstract: Publication date: Available online 5 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Anna M. Kaczmarek, Piotr W. Alvarez Porebski, Tineke Mortier, Frederic Lynen, Rik Van Deun, Kristof Van Hecke
      A complete series of lanthanide Schiff base salen-type complexes were prepared with trivalent lanthanide ions (Ln3+) and the N,N′-bis-(3-methoxysalicylidene)ethylene-1,2-diamine ligand (Ln3+ =La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+, Lu3+). Three unique crystal structures of La3+ and Pr3+ N,N′-bis-(3-methoxysalicylidene)ethylene-1,2-diamine complexes, with the La3+ complex prepared in two different synthetic approaches, are reported, namely a dimeric [La(H2L)(NO3)3]2 (H2L= N,N′-bis-(3-methoxysalicylidene)ethylene-1,2-diamine) complex, an asymmetric two-centered [La2(H2L)2(NO3)6] complex and a discrete mononuclear [Pr(H2L)(NO3)2(H2O)2] complex. For Nd3+ and Sm3+, an isotypic mononuclear [Nd(H2L)(NO3)3] and 1D polymeric [Sm(H2L)(NO3)3(MeOH)]n structure was obtained, respectively. The whole series of complexes was tested for their ability to cleave the 20-mer RNA oligonucleotide 5′-AGC-GAU-AAG-AUU-CAU-AUA-UC-3′. Additionally three complexes (Ln3+ =Nd3+, Sm3+, Ho3+) were tested for the cleavage of the 12-mer RNA oligonucleotide 5′-GCA-CCC-UGU-CAG-3′. A detailed luminescence study was additionally carried out and revealed that the Eu3+ complex emitted bright red light upon excitation at both 285.8nm and 394.4nm. The Nd3+, Er3+, and Yb3+ complexes showed strong emission in the near-infrared region after excitation at 380nm.
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      PubDate: 2016-08-08T09:43:52Z
       
  • Enzymatic oxidation of ansa-ferrocifen leads to strong and selective
           thioredoxin reductase inhibition in vitro
    • Abstract: Publication date: Available online 5 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Valeria Scalcon, Anna Citta, Alessandra Folda, Alberto Bindoli, Michèle Salmain, Ilaria Ciofini, Sébastien Blanchard, José de Jesus Cazares-Marinero, Yong Wang, Pascal Pigeon, Gérard Jaouen, Anne Vessières, Maria-Pia Rigobello
      This paper reports the inhibitory effecton the cytosolic thioredoxin reductase (TrxR1) in vitro by the ansa-ferrocifen derivative (ansa-FcdiOH, 1). We found that 1 decreased only slightly enzyme activity (IC50 =8μM), while 1*, the species generated by enzymatic oxidation by HRP (horseradish peroxidase)/H2O2 mixture, strongly inhibited TrxR1 (IC50 =0.15μM). At the same concentrations, neither 1 nor 1* had effect on glutathione reductase (GR). The most potent TrxR1 inhibitor did not appear to be the corresponding quinone methide as it was the case for ferrocifens of the acyclic series, or the stabilized carbocation as in the osmocifen series, but rather the quinone methide radical. This hypothesis was confirmed by ab-initio calculations of the species generated by oxidation of 1 and by EPR spectroscopy. BIAM (biotin-conjugated iodoacetamide) assay showed that 1* targeted both cysteine and selenocysteine of the C-terminal redox center of TrxR1.
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      PubDate: 2016-08-08T09:43:52Z
       
  • Visible light-induced formation of corrole-manganese(V)-oxo complexes:
           Observation of multiple oxidation pathways
    • Abstract: Publication date: Available online 5 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Wai Kwong Ka, Fung Lee Ngo, Davis Ranburger, Jonathan Malone, Rui Zhang
      Two manganese(V)-oxo corroles [MnV(Cor)O] that differ in their electronic environments were produced by visible light irradiation of highly photo-labile corrole-manganese(IV) bromates. The corrole ligands under study include 5,10,15-tris(pentafluorophenyl)corrole (TPFC), and 5,10,15-triphenylcorrole (TPC). The kinetics of oxygen transfer atom (OAT) reactions with various organic reductants by these photo-generated MnV(Cor)O were also studied in CH3CN and CH2Cl2 solutions. MnV(Cor)O exhibits remarkable solvent and ligand effect on its reactivity and spectral behavior. In the more electron-deficient TPFC system and in the polar solvent CH3CN, MnV(Cor)O returned MnIII corrole in the end of oxidation reactions. However, in the less polar solvent CH2Cl2 or in the less electron-deficient TPC system, MnIV product was formed instead. Furthermore, with the same substrates and in the same solvent, the order of reactivity of MnV(Cor)O was TPC>TPFC, which is inverted from that expected based on the electron-demand of corrole ligands. Our spectral and kinetic results in this study provide compelling evidence in favor of multiple oxidation pathways, where MnV(Cor)O may serve as direct two-electron oxidant or undergo a disproportionation reaction to form a manganese(VI)-oxo corrole as the true oxidant. The choice of pathways is strongly dependent on the nature of the solvent and the corrole ligand.
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      PubDate: 2016-08-08T09:43:52Z
       
  • Physico-chemical properties of MnII complexes formed with cis- and
           trans-DO2A†: Thermodynamic, electrochemical and kinetic studies
    • Abstract: Publication date: Available online 2 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Zoltán Garda, Attila Forgács, Quyen N. Do, Ferenc K. Kálmán, Sarolta Timári, Zsolt Baranyai, Lorenzo Tei, Imre Tóth, Zoltán Kovács, Gyula Tircsó
      Manganese (MnII) is a promising alternative to gadolinium (GdIII) as a magnetic resonance imaging (MRI) agent. Unlike gadolinium, this biogenic metal might be better tolerated by the body, reducing the risk of toxicity associated with dissociation of the complex. Herein we report detailed equilibrium and kinetic studies performed with MnII complexes of 1,4,7,10-tetraazacyclododecane-1,4-diacetic acid (1,4-DO2A or cis-DO2A) and 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (1,7-DO2A or trans-DO2A). The protonation constants of the ligands as well as stability constants of their MnII complexes have been determined by pH-potentiometry. The stability constants of [Mn(cis-DO2A)] are slightly higher than that of [Mn(trans-DO2A)] (log K MnL =15.68 and 15.22, respectively). Cyclic voltammetric (CV) experiments performed on [Mn(cis-DO2A)] and [Mn(trans-DO2A)] revealed quasireversible systems with a half-wave potential of +636 and +705mV versus Ag/AgCl, respectively. These values indicate that the MnII ion in these complexes is more stabilized against the oxidation than in [Mn(EDTA)]2−. The kinetic inertness of the complexes has been studied in transmetallation reactions with CuII or ZnII ions. Kinetic measurements indicate that both MnII complexes primarily undergo acid catalyzed dissociation and positions of the acetate pendant arms do not influence kinetic inertness. The kinetic inertness of these complexes is comparable to that of [Mn(NOTA)]− and significantly (about twenty times) lower than that of [Mn(DOTA)]2−. In conclusion, [Mn(cis-DO2A)] displays some very interesting features (thermodynamic and redox stability as well as kinetic inertness) which makes this complex a promising platform for the development of more efficient MnII complexes as alternatives to Gd-based MRI agents.
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      PubDate: 2016-08-04T09:26:11Z
       
  • Design, syntheses, characterization, and cytotoxicity studies of novel
           heterobinuclear oxindolimine copper(II)-platinum(II) complexes
    • Abstract: Publication date: Available online 3 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Esther Escribano Aranda, Tiago Araújo Matias, Koiti Araki, Adriana Pires Vieira, Elaine Andrade de Mattos, Pio Colepicolo, Carolina Portela Luz, Fábio Luiz Navarro Marques, Ana Maria da Costa Ferreira
      Herein, the design and syntheses of two new mononuclear oxindolimine-copper(II) (1 and 2) and corresponding heterobinuclear oxindolimine Cu(II)Pt(II) complexes (3 and 4), are described. All the isolated complexes were characterized by spectroscopic techniques (UV/Vis, IR, EPR), in addition to elemental analysis and mass spectrometry. Cyclic voltammetry (CV) measurements showed that in all cases, one-electron quasi-reversible waves were observed, and ascribed to the formation of corresponding copper(I) complexes. Additionally, waves related to oxindolimine ligand reduction was verified, and confirmed using analogous oxindolimine-Zn(II) complexes. The Pt(IV/II) reduction, and corresponding oxidation, for complexes 3 and 4 occurred at very close values to those observed for cisplatin. By complementary fluorescence studies, it was shown that glutathione (GSH) cannot reduce any of these complexes, under the experimental conditions (room temperature, phosphate buffer 50mM, pH7.4), using an excess of 20-fold [GSH]. All these complexes showed characteristic EPR spectral profile, with parameters values gǁ >g⊥ suggesting an axially distorted environment around the copper(II) center. Interactions with calf thymus-DNA, monitored by circular dichroism (CD), indicated different effects modulated by the ligands. Finally, the cytotoxicity of each complex was tested toward different tumor cells, in comparison to cisplatin, and low values of IC50 in the range 0.6 to 4.0μM were obtained, after 24 or 48h incubation at 37°C. The obtained results indicate that such complexes can be promising alternative antitumor agents.
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      PubDate: 2016-08-04T09:26:11Z
       
  • Kinetics and thermodynamics of zinc(II) and arsenic(III) binding to XPA
           and PARP-1 zinc finger peptides
    • Abstract: Publication date: Available online 2 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Juliana Huestis, Xixi Zhou, Li Chen, Changjian Feng, Laurie G. Hudson, Ke Jian Liu
      Inhibition of DNA repair is an established mechanism of arsenic co-carcinogenesis, and may be perpetuated by the binding of As(III) to key zinc finger (zf) DNA repair proteins. Validated molecular targets of As(III) include the first zinc finger domain of Poly (ADP-Ribose) Polymerase 1 (PARP-1), and the zinc finger domain of Xeroderma Pigmentosum Complementation Group A (XPA). In order to gain an understanding of the thermodynamic and kinetic parameters of the interaction of As(III) with these two zinc finger motifs, a fluorescence based approach was used to investigate Zn(II) and As(III) binding to synthetic model peptides corresponding to the zf motif of XPA and first zf motif of PARP-1, referred to in this paper as XPAzf and PARP-1zf-1, respectively. While XPAzf and PARP-1zf-1 display similar relative affinities for As(III), PARP-1zf-1 shows a potential kinetic advantage over XPAzf for As(III) binding, with a rate constant for the fast phase of formation of As(III)-PARP-1zf-1 approximately 4-fold higher than for As(III)-XPAzf. However, the binding of Zn(II) with either peptide proceeds at a faster rate than As(III). Notably, XPAzf demonstrates comparable affinities for binding both metals, while PARP-1zf-1 shows a slightly higher affinity for Zn(II), suggesting that the relative concentrations of Zn(II) and As(III) in a system may significantly influence which species predominates in zinc finger occupancy. These results provide insight into the mechanisms underlying interactions between zinc finger structures and As(III), and highlight the potential utility of zinc supplementation in mitigating adverse effects of As(III) on zinc finger functions in vivo.
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      PubDate: 2016-08-04T09:26:11Z
       
  • In vitro antibacterial and time kill evaluation of mononuclear
           phosphanegold(I) dithiocarbamates
    • Abstract: Publication date: Available online 3 August 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Bao-Jing Chen, Nazzatush Shimar Jamaludin, Chai-Hoon Khoo, Tian-Hong See, Jiun-Horng Sim, Yoke-Kqueen Cheah, Siti Nadiah Abdul Halim, Hoi-Ling Seng, Edward R.T. Tiekink
      Four compounds, R3PAu[S2CN(CH2CH2OH)2], R=Ph (1) and Cy (2), and Et3PAuS2CNRꞌ2, Rꞌ=Rꞌ=Et (3) and Rꞌ2 =(CH2)4 (4), have been evaluated for antibacterial activity against a panel of 24 Gram positive (8) and Gram negative (16) bacteria. Based on minimum inhibitory concentration (MIC) scores, compounds 1 and 2 were shown to be specifically potent against Gram positive bacteria whereas compounds 3 and, to a lesser extent, 4 exhibited broad range activity. All four compounds were active against methicillin resistant Staphylococcus aureus (MRSA). Time kill assays revealed the compounds to exhibit both time- and concentration-dependent pharmacokinetics against susceptible bacteria. Each compound was bactericidal against one or more bacteria with 3 being especially potent after 8h exposure; compounds 1 and 3 were bactericidal against MRSA. Compound 3 was the most effective bactericide across the series especially toward B. subtilis, S. saprophyticus, A. hydrophila, P. vulgaris, and V. parahaemolyticus. This study demonstrates the potential of this class of compounds as antibacterial agents, either broad range or against specific bacteria.
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      PubDate: 2016-08-04T09:26:11Z
       
  • Cobalt(II) complexes of sparfloxacin: Characterization, structure,
           antimicrobial activity and interaction with DNA and albumins
    • Abstract: Publication date: Available online 28 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Eleftherios Kouris, Stavros Kalogiannis, Franc Perdih, Iztok Turel, George Psomas
      The cobalt(II) complexes with the quinolone sparfloxacin (Hsf) in the absence or presence of the nitrogen-donor heterocyclic ligands 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen) or 2,2′-bipyridylamine (bipyam) were prepared and characterized physicochemically and spectroscopically. The crystal structures of complexes [Co(sf)2(bipy)]∙3MeOH·2H2O and [Co(sf)2(phen)]∙4MeOH were determined by X–ray crystallography. The antimicrobial activity of the complexes was tested against four different microorganisms (Escherichia coli, Xanthomonas campestris, Staphylococcus aureus and Bacillus subtilis) and was found similar or higher than that of free Hsf. The binding of the complexes to calf-thymus DNA was monitored by UV spectroscopy and DNA-viscosity measurements and indirectly by competitive studies with ethidium bromide; intercalation is suggested as the most possible interaction mode. Fluorescence emission spectroscopy was used to evaluate the interaction of the complexes with human or bovine serum albumin proteins and the corresponding binding constants were determined.
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      PubDate: 2016-07-30T08:53:02Z
       
  • Impact of cyclometalated ruthenium(II) complexes on lactate dehydrogenase
           activity and cytotoxicity in gastric and colon cancer cells
    • Abstract: Publication date: Available online 26 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Hugo Rico Bautista, Rafael Omar Saavedra Díaz, Longzhu Q. Shen, Christophe Orvain, Christian Gaiddon, Ronan Le Lagadec, Alexander D. Ryabov
      Lactate dehydrogenase (LDH) is a redox enzyme often overexpressed in cancer cells allowing their survival in stressful metabolic tumor environment. Ruthenium(II) complexes have been shown to impact on the activity of purified horseradish peroxidase and glucose oxidase but the physiological relevance remains unclear. In this study we investigated how ruthenium complexes impact on the activity of LDH in vitro and in cancer cells and performed a comparative study using polypyridine ruthenium(II) complex [Ru(bpy)3]2+ (1) and its structurally related cyclometalated 2-phenylpyridinato counterpart [Ru(phpy)(bpy)2]+ (2) (bpy=2,2′-bipyridine, phpyH =2-phenylpyridine). We show that the cytotoxicity in gastric and colon cancer cells induced by 2 is significantly higher compared to 1. The kinetic inhibition mechanisms on purified LDH and the corresponding inhibition constants K i or i 0.5 values were calculated. Though complexes 1 and 2 are structurally very similar (one Ru⎼C bond in 2 replaces one Ru⎼N bond in 1), their inhibition modes are different. Cyclometalated complex 2 behaves exclusively as a non-competitive inhibitor of LDH from rabbit muscle (LDHrm), strongly suggesting that 2 does not interact with LDH in the vicinities of either lactate/pyruvate or NAD+/NADH binding sites. Sites of interaction of 1 and 2 with LDHrm were revealed theoretically through computational molecular docking. Inhibition of LDH activity by 2 was confirmed in cancer cells. Altogether, these results revealed an inhibition of LDH activity by ruthenium complex through a direct interaction structurally tuned by a Ru⎼C bond.
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      PubDate: 2016-07-26T08:43:46Z
       
  • Novel silver(I) complexes of coumarin oxyacetate ligands and their
           phenanthroline adducts: Biological activity, structural and spectroscopic
           characterisation
    • Abstract: Publication date: Available online 16 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Muhammad Mujahid, Natasha Trendafilova, Agnieszka Foltyn Arfa-Kia, Georgina Rosair, Kevin Kavanagh, Michael Devereux, Maureen Walsh, Siobhán McClean, Bernadette S. Creaven, Ivelina Georgieva
      Novel silver(I) complexes of coumarin oxyacetate ligands and their phenanthroline adducts have been prepared and characterised by microanalytical data and spectroscopic techniques (IR, 1H, 13C NMR, UV–Vis). The crystal structure of one Ag(I) complex was determined by X-ray diffraction analysis. The experimental spectroscopic data have been interpreted on the basis of molecular structure modeling and subsequent spectra simulation with density functional theory method. The binding modes of the coumarins and phenanthroline ligands (monodentate, bidentate, bridging) to Ag(I) have been theoretically modelled and discussed as to the most probable ligand binding in the series of complexes studied. The antimicrobial and antifungal activities have been determined and the complexes were found to have mostly moderate antibacterial activity but some of the phenanthroline adducts were found to have antifungal activity against the clinically important fungus C. albicans, comparable to that of the commercial agents, Amphotericin B and Ketoconazole. Preliminary investigations into the possible mechanism of action of the silver complexes indicated that they did not interact with DNA via nuclease activity or intercalation but the ability to act as a superoxide dismutase mimetic may be related to their antimicrobial activity.
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      PubDate: 2016-07-17T06:57:54Z
       
  • Kinetic Studies on the Reaction of Cob(II)alamin with Hypochlorous Acid:
           Evidence for one electron oxidation of the metal center and corrin ring
           destruction
    • Abstract: Publication date: Available online 15 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Rohan S. Dassanayake, Mohamed M. Farhath, Jacob T. Shelley, Soumitra Basu, Nicola E. Brasch
      Kinetic and mechanistic studies on the reaction of a major intracellular vitamin B12 form, cob(II)alamin (Cbl(II)), with hypochlorous acid/hypochlorite (HOCl/OCl−) have been carried out. Cbl(II) (Co(II)) is rapidly oxidized by HOCl to predominately aquacobalamin/hydroxycobalamin (Cbl(III), Co(III)) with a second-order rate constant of 2.4 x 107 M−1 s−1 (25.0°C). The stoichiometry of the reaction is 1:1. UHPLC/HRMS analysis of the product mixture of the reaction of Cbl(II) with 0.9mol equiv. HOCl provides support for HOCl being initially reduced to Cl• and subsequent H atom abstraction from the corrin macrocycle occurring, resulting in small amounts of corrinoid species with two or four H atoms fewer than the parent cobalamin. Upon the addition of excess (H)OCl further slower reactions are observed. Finally, SDS-PAGE experiments show that HOCl-induced damage to bovine serum albumin does not occur in the presence of Cbl(II), providing support for Cbl(II) being an efficient HOCl trapping agent.
      Graphical abstract image

      PubDate: 2016-07-17T06:57:54Z
       
  • Design and characterization of highly in vitro antitumor active ternary
           copper(II) complexes containing 2′-hydroxychalcone ligands
    • Abstract: Publication date: Available online 9 July 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Radka Křikavová, Ján Vančo, Zdeněk Trávníček, Jakub Hutyra, Zdeněk Dvořák
      A series of innovative copper(II) complexes of the general composition [Cu(Ln)(phen)]NO3 (1–8; phen=1,10-phenanthroline), involving 2′-hydroxychalcone {(E)-1-(2′-hydroxyphenyl)-3-phenylprop-2-en-1-one} derivatives (HLn) was synthesized, thoroughly characterized and screened for in vitro cytotoxicity against a panel of ten human cancer cell lines. The most promising results were achieved for complex 2 with the best IC50 value of 1.1±0.7μM (against A2780 cell line). The toxicity testing on a primary culture of human hepatocytes (HH) revealed that complex 2 is the least toxic from the whole series with the IC50 value of 63.7μM. The complexes were shown to be able to efficaciously cleave pUC19 plasmid DNA as well as intercalate into calf thymus DNA with the same affinity and efficacy as ethidium bromide and interact by the ligand exchange mechanism with l-cysteine at physiological concentration levels.
      Graphical abstract image

      PubDate: 2016-07-13T06:37:07Z
       
  • Enhanced anti-cancer activities of a gold(III) pyrrolidinedithiocarbamato
           complex incorporated in a biodegradable metal-organic framework
    • Abstract: Publication date: October 2016
      Source:Journal of Inorganic Biochemistry, Volume 163
      Author(s): Raymond Wai-Yin Sun, Ming Zhang, Dan Li, Mian Li, Alice Sze-Tsai Wong
      An anti-cancer active gold(III) pyrrolidinedithiocarbamato complex [(PDTC)AuIIICl2] (1) has been synthesized and characterized by means of X-ray crystallography. Compared to the pyrrolidinedithiocarbamate ligand itself, this gold(III) complex displays an up to 33-fold higher anti-cancer potency towards a panel of cancer cell lines including the cisplatin-resistant ovarian carcinoma cell line (A2780cis). As demonstrated by a set of Transwell® assay-based cytotoxicity experiments, incorporating this gold(III) complex in a zinc-based biodegradable metal-organic framework (MOF) displays a significant enhancement in anti-cancer activity towards A2780cis than the gold(III) complex alone.
      Graphical abstract image

      PubDate: 2016-07-05T04:56:03Z
       
  • A combined crystallographic analysis and ab initio calculations to
           interpret the reactivity of functionalized hexavanadates and their
           inhibitor potency toward Na+/K+-ATPase
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161
      Author(s): Xiao Xu, Nada Bošnjaković-Pavlović, Mirjana B. Čolović, Danijela Z. Krstić, Vesna M. Vasić, Jean-Michel Gillet, Pingfan Wu, Yongge Wei, Anne Spasojević-de Biré
      In vitro influence of five synthesized functionalized hexavanadates (V6) on commercial porcine cerebral cortex Na+/K+-ATPase activity has been studied. Dose dependent Na+/K+-ATPase inhibition was obtained for all investigated compounds. Calculated half maximal inhibitory concentration IC50 values, in mol/L, for Na+/K+-ATPase were 7.6×10−5, 1.8×10−5, 2.9×10−5, 5.5×10−5 for functionalized hexavanadates (V6) with tetrabutylammonium (TBA) [V6–CH3][TBA]2, [V6–NO2][TBA]2, [V6–OH][TBA]2 and [V6–C3][TBA]2 respectively. [V6–OH][Na]2 inhibited Na+/K+-ATPase activity up to 30% at maximal investigated concentration 1×10−3 mol/L. This reactivity has been interpreted using a study of the non-covalent interactions of functionalized hexavanadate hybrids through Cambridge Structural Database (CSD) analysis. Bibliographic searching has led to 18 different structures and 99 contacts. We have observed that C–H⋯O contacts consolidate the structures. We have also performed density functional theory (DFT) calculations and have determined electrostatic potential values at the molecular surface on a series of functionalized V6. These results enlightened their chemical reactivity and their potential biological applications such as the inhibition of the ATPase.
      Graphical abstract image

      PubDate: 2016-06-17T18:00:43Z
       
  • Behavior of the potential antitumor VIVO complexes formed by flavonoid
           ligands. 3. Antioxidant properties and radical production capability
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161
      Author(s): Daniele Sanna, Valeria Ugone, Angela Fadda, Giovanni Micera, Eugenio Garribba
      The radical production capability and the antioxidant properties of some VIVO complexes formed by flavonoid ligands were examined. In particular, the bis-chelated species of quercetin (que), [VO(que)2]2−, and morin (mor), [VO(mor)2], were evaluated for their capability to reduce the stable radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and produce the hydroxyl radical •OH by Fenton-like reactions, where the reducing agent is VIVO2+. The results were compared with those displayed by other VIVO complexes, such as [VO(H2O)5]2+, [VO(acac)2] (acac=acetylacetonate) and [VO(cat)2]2− (cat=catecholate). The capability of the VIVO flavonoids complexes to reduce DPPH is much larger than that of the VIVO species formed by non-antioxidant ligands and it is due mainly to the flavonoid molecule. Through the 5,5-dimethyl-1-pyrroline N-oxide (DMPO) spin trapping assay of the hydroxyl radical it was possible to demonstrate that in acidic solution VIVO2+ has an effectiveness in producing •OH radicals comparable to that of Fe2+. When VIVO complexes of flavonoids were taken into account, the amount of hydroxyl radicals produced in Fenton-like reactions depends on the specific structure of the ligand and on their capability to reduce H2O2 to give •OH. Both the formation of reactive oxygen species (ROS) under physiological conditions by VIVO complexes of flavonoid ligands and their radical scavenging capability can be put in relationship with their antitumor effectiveness and it could be possible to modulate these actions by changing the features of the flavonoid coordinated to the VIVO2+ ion, such as the entity, nature and position of the substituents and the number of phenolic groups.
      Graphical abstract image

      PubDate: 2016-06-17T18:00:43Z
       
  • Editorial Board
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161




      PubDate: 2016-06-17T18:00:43Z
       
  • Cytotoxic trans-platinum(II) complex with 3-hydroxymethylpyridine:
           Synthesis, X-ray structure and biological activity evaluation
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161
      Author(s): Sabina Grabner, Barbara Modec, Nataša Bukovec, Peter Bukovec, Maja Čemažar, Simona Kranjc, Gregor Serša, Janez Sčančar
      To assess the potential cytostatic properties of Pt(II) complexes with 3-hydroxymethylpyridine (3-hmpy) as the only carrier ligand, novel cis-[PtCl2(3-hmpy)2] (1) and trans-[PtCl2(3-hmpy)2] (2) have been prepared. Elemental analysis, FTIR spectroscopy, multinuclear NMR spectroscopy and X-ray crystallography were used to determine their structures. Based on the results obtained with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay and clonogenic assay on T24 human bladder carcinoma cells (T24), the most potent compound 2 was further tested for cytotoxicity in human ovarian carcinoma cell lines - cisplatin sensitive (IGROV 1) and its resistant subclone (IGROV 1/RDDP). The cytotoxicity of compound 2 in IGROV 1/RDDP is comparable to cisplatin. Furthermore, compound 2 induced severe conformational changes in plasmid DNA, which resulted in a delayed onset of apoptosis in T24 cells, and higher amounts of Pt in tumours and serum compared to cisplatin. In addition, in vivo antitumour effectiveness was comparable to that of cisplatin with a smaller reduction of animals' body weight, thus demonstrating that it is a promising transplatin analogue which deserves further studies.
      Graphical abstract image

      PubDate: 2016-06-17T18:00:43Z
       
  • Effects of Cu(II) and cisplatin on the stability of Specific protein 1
           (Sp1)-DNA binding: Insights into the regulation of copper homeostasis and
           platinum drug transport
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161
      Author(s): Dong Yan, Isamu Aiba, Helen H.W. Chen, Macus Tien Kuo
      The human high-affinity copper transporter 1 (hCtr1) transports both Cu(I) and cisplatin (cDDP). Because Cu deficiency is lethal yet Cu overload is poisonous, hCtr1 expression is transcriptionally upregulated in response to Cu deficiency but is downregulated under Cu replete conditions in controlling Cu homeostasis. The up- and down-regulation of hCtr1 is regulated by Specific protein 1 (Sp1), which itself is also correspondingly regulated under these Cu conditions. hCtr1 expression is also upregulated by cDDP via upregulation of Sp1. The underlying mechanisms of these regulations are unknown. Using gel-electrophoretic mobility shift assays, we demonstrated here that Sp1-DNA binding affinity is reduced under Cu replete conditions but increased under reduced Cu conditions. Similarly, Sp1-DNA binding affinity is increased by cDDP treatment. This in vitro system demonstrated, for the first time, that regulation of Sp1/hCtr1 expression by these agents is modulated by the stability of Sp1-DNA binding, the first step in the Sp1-mediated transcriptional regulation process.
      Graphical abstract image

      PubDate: 2016-06-17T18:00:43Z
       
  • Synthesis, structural characterization, cytotoxic properties and DNA
           binding of a dinuclear copper(II) complex
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161
      Author(s): B.J.M. Leite Ferreira, P. Brandão, M. Meireles, Fátima Martel, Ana Correia-Branco, Diana M. Fernandes, T.M. Santos, V. Félix
      In this study a novel dinuclear copper(II) complex with adenine and phenanthroline has been synthesized and its structure determined by single crystal X-ray diffraction. In the dinuclear complex [Cu₂(μ-adenine)₂(phen)₂(H2O)2](NO3)4·0.5H2O (phen=1,10-phenanthroline) (1) the two Cu(II) centres exhibit a distorted square pyramidal coordination geometry linked by two nitrogen donors from adenine bridges leading to a Cu–Cu distance of 3.242(3)Å. Intramolecular and intermolecular π⋯π interactions as well as an H-bonding network were observed. The antitumor capacity of the complex has been tested in vitro against human cancer cell lines, cervical carcinoma (HeLa) and colorectal adenocarcinoma (Caco-2), by metabolic tests, using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide as reagent. The complex 1 has remarkable low IC50 values of 0.87±0.06μM (HeLa) and 0.44±0.06μM (Caco-2), when compared with values for cisplatin against the same cell lines. The interaction of complex 1 with calf thymus DNA (CT DNA) was further investigated by absorption and fluorescence spectroscopic methods. A binding constant of 5.09×105 M−1 was obtained from UV–vis absorption studies.
      Graphical abstract image

      PubDate: 2016-06-17T18:00:43Z
       
  • Contents
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161




      PubDate: 2016-06-17T18:00:43Z
       
  • The neglected role of copper ions in wound healing
    • Abstract: Publication date: August 2016
      Source:Journal of Inorganic Biochemistry, Volume 161
      Author(s): Allison Paige Kornblatt, Vincenzo Giuseppe Nicoletti, Alessio Travaglia
      Wound healing is a complex biological process that aims to repair damaged tissue. Even though many biological and biochemical mechanisms associated with the steps of physiological wound healing are known, there is still significant morbidity and mortality due to dysregulation of physiological mechanisms. It might be useful to revise the activity of old players and their links with new, often neglected, molecular entities. This review revises new findings supporting the hypothesis that copper ions regulate the activity and/or the expression of proteins crucially involved in the wound repair process. A better understanding of these interactions might suggest potential new targets for therapeutic intervention on scars or non-healing wounds.
      Graphical abstract image

      PubDate: 2016-06-17T18:00:43Z
       
  • Characterization and biological properties of copper(II)-ketoprofen
           complexes
    • Abstract: Publication date: Available online 4 June 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Spyros Perontsis, Antonios G. Hatzidimitriou, Olga-Aggeliki Begou, Athanasios N. Papadopoulos, George Psomas
      From the reaction of Cu(II) with non-steroidal anti-inflammatory drug ketoprofen (Hketo), complex [Cu2(keto)4(H2O)2] was isolated, while the presence of a N,N′-donor heterocyclic ligand 2,2′-bipyridylamine (bipyam), 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy) led to the formation of complexes of the formula [Cu(keto)2(N,N′-donor)(H2O)]. The complexes were characterized by physicochemical and spectroscopic techniques and the crystal structure of [Cu(keto)2(bipyam)(H2O)] was determined by X-ray crystallography. The ability of ketoprofen and its complexes to scavenge 1,1-diphenyl-picrylhydrazyl, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) and hydroxyl radicals was evaluated; the complexes were more active compounds than free Hketo. The interaction of the complexes with serum albumins was investigated by fluorescence emission spectroscopy and the binding constant of the compounds to the albumins were calculated. Diverse techniques including UV spectroscopy, cyclic voltammetry and viscosity measurements as well as fluorescence emission spectroscopy for the competitive studies of the compounds with ethidium bromide, were employed in our attempt to examine the interaction of the compounds with calf-thymus DNA; as a conclusion, intercalation is the most possible mode of binding.
      Graphical abstract image

      PubDate: 2016-06-08T09:57:56Z
       
  • Nickel-diflunisal complexes: synthesis, characterization, in vitro
           antioxidant activity and interaction with DNA and albumins
    • Abstract: Publication date: Available online 4 June 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Spyros Perontsis, Antonios G. Hatzidimitriou, Athanasios N. Papadopoulos, George Psomas
      The reaction of NiCl2 with the non-steroidal anti-inflammatory drug diflunisal (Hdifl) resulted in the formation of complex [Ni(difl-O)2(MeOH)4], 1. The co-existence of a N,N′-donor heterocyclic ligand 2,2′-dipyridylketone oxime (Hpko), 1,10-phenanthroline (phen), 2,2′-bipyridine (bipy) and 2,2′-bipyridylamine (bipyam) led to the formation of complexes [Ni(difl-O)2(Hpko-N,N′)2], 2, [Ni(difl)2(phen)(MeOH)2], 3, [Ni(difl)2(bipy)(MeOH)2], 4 and [Ni(difl-O,O′)2(bipyam)], 5, respectively. The complexes were characterized by physicochemical and spectroscopic techniques and the crystal structures of complexes 1 and 2 were determined by X-ray crystallography. The ability of the complexes to scavenge in vitro 1,1-diphenyl-picrylhydrazyl, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) and hydroxyl radicals was investigated; the complexes were more active scavengers than free Hdifl. The interaction of the complexes with serum albumins was investigated by fluorescence emission spectroscopy and the binding constant of the compounds to the albumins were calculated. UV spectroscopy, cyclic voltammetry and viscosity measurements as well as fluorescence emission spectroscopy for the competitive studies of the complexes with ethidium bromide were employed so as to monitor the interaction of the compounds with calf-thymus DNA and revealed intercalation as the most possible mode of binding.
      Graphical abstract image

      PubDate: 2016-06-08T09:57:56Z
       
  • Vanadium(IV)-chlorodipicolinate inhibits 3T3-L1 preadipocyte adipogenesis
           by activating LKB1/AMPK signaling pathway
    • Abstract: Publication date: Available online 5 June 2016
      Source:Journal of Inorganic Biochemistry
      Author(s): Liang Zhang, Ying Huang, Fang Liu, Fang Zhang, Wenjun Ding
      Our previous studies demonstrated that vanadium(IV) complex with 4-chlorodipicolinic acid (VOdipic-Cl) alleviates lipid abnormalities in streptozotocin (STZ)-induced diabetic rats. However, the molecular mechanisms are not fully understood. In the present study, the effect of VOdipic-Cl on adipogenesis and mechanisms of action in 3T3-L1 preadipocytes were investigated. The 3T3-L1 preadipocytes were induced to differentiate in the presence or absence of VOdipic-Cl for 8days. The cells were determined for proliferation, differentiation, lipid accumulation as well as the protein expressions of molecular targets that are involved in fatty acid synthesis. The results demonstrated that VOdipic-Cl at concentrations ranging from 2.5μM to 10μM reduced the intracellular lipid content by 10%, 22% and 30% compared to control. VOdipic-Cl down-regulated the expression of peroxisome proliferator-activated receptor (PPARγ), CCAAT element binding protein a (C/EBPα), sterol regulatory element binding protein 1c (SREBP-1c), fatty acid synthase (FAS) and fatty acid-binding protein 4 (FABP4) and activated the phosphorylation of acetyl coenzyme A carboxylase (ACC), adenosine monophosphate-activated protein kinase (AMPK) and liver kinase B1 (LKB1) in a dose-dependent manner. Further studies showed that AMPK small interfering RNA (siRNA) markedly up-regulated PPARγ, C/EBPα, FAS and FABP4 expression in the presence of VOdipic-Cl, respectively. When LKB1 was silenced with siRNA, the effect of VOdipic-Cl on AMPK phosphorylation was diminished. Taken together, these results suggested that VOdipic-Cl can inhibit 3T3-L1 preadipocyte differentiation and adipogenesis through activating the LKB1/AMPK-dependent signaling pathway. These findings raise the possibility that VOdipic-Cl may be a promising therapy in treatment of obesity.
      Graphical abstract image

      PubDate: 2016-06-08T09:57:56Z
       
  • 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
       
 
 
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