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Journal of Biological Inorganic Chemistry: JBIC

Qiao-Yan Yi, Wen-Yao Zhang, Miao He, Fan Du, Xiu-Zhen Wang, Yang-Jie Wang, Yi-Ying Gu, Lan Bai, Yun-Jun Liu
Three iridium(III) polypyridyl complexes [Ir(ppy)2 (PYTA)](PF6 ) (1) (ppy = 2-phenylpyridine), [Ir(bzq)2 (PYTA)](PF6 ) (2) (bzq = benzo[h]quinolone) and [Ir(piq)2 (PYTA)](PF6 ) (3) (piq = 1-phenylisoquinoline, PYTA = 2,4-diamino-6-(2'-pyridyl)-1,3,5-triazine) were synthesized and characterized by elemental analysis, IR, 1 H NMR and 13 C NMR. The cytotoxic activity of the complexes toward cancer SGC-7901, Eca-109, A549, HeLa, HepG2, BEL-7402 and normal LO2 cell lines was investigated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method...
December 18, 2018: Journal of Biological Inorganic Chemistry: JBIC
Mziyanda Mbaba, Jo-Anne de la Mare, Jason N Sterrenberg, Deborah Kajewole, Shantal Maharaj, Adrienne L Edkins, Michelle Isaacs, Heinrich C Hoppe, Setshaba D Khanye
A series of tailored novobiocin-ferrocene conjugates was prepared in moderate yields and investigated for in vitro anticancer and antiplasmodial activity against the MDA-MB-231 breast cancer line and Plasmodium falciparum 3D7 strain, respectively. While the target compounds displayed moderate anticancer activity against the breast cancer cell line with IC50 values in the mid-micromolar range, compounds 10a-c displayed promising antiplasmodial activity as low as 0.889 µM. Furthermore, the most promising compounds were tested for inhibitory effects against a postulated target, heat shock protein 90 (Hsp90)...
December 12, 2018: Journal of Biological Inorganic Chemistry: JBIC
Lawrence Que
"In the original online publication, the Foreword was incorrectly attributed. The correct author is Lawrence Que, Jr."
December 7, 2018: Journal of Biological Inorganic Chemistry: JBIC
Taylor Devlin, Cristina R Hofman, Zachary P V Acevedo, Kelsey R Kohler, Lizhi Tao, R David Britt, Kevin R Hoke, Laura M Hunsicker-Wang
The CuA center is the initial electron acceptor in cytochrome c oxidase, and it consists of two copper ions bridged by two cysteines and ligated by two histidines, a methionine, and a carbonyl in the peptide backbone of a nearby glutamine. The two ligating histidines are of particular interest as they may influence the electronic and redox properties of the metal center. To test for the presence of reactive ligating histidines, a portion of cytochrome c oxidase from the bacteria Thermus thermophilus that contains the CuA site (the TtCuA protein) was treated with the chemical modifier diethyl pyrocarbonate (DEPC) and the reaction followed through UV-visible, circular dichroism, and electron paramagnetic resonance spectroscopies at pH 5...
December 6, 2018: Journal of Biological Inorganic Chemistry: JBIC
Xi-Xi Yang, Qiu-Yun Mao, Xiao-Ting An, Xi-Chen Li, Per E M Siegbahn, Guang-Ju Chen, Hong-Wei Tan
The mechanism of the H2 O2 disproportionation catalyzed by the manganese catalase (MnCat) KatB was studied using the hybrid density functional theory B3LYP and the quantum chemical cluster approach. Compared to the previous mechanistic study at the molecular level for the Thermus thermophilus MnCat (TTC), more modern methodology was used and larger models of increasing sizes were employed with the help of the high-resolution X-ray structure. In the reaction pathway suggested for KatB using the Large chemical model, the O-O homolysis of the first substrate H2 O2 occurs through a μ-η1 :η1 coordination mode and requires a barrier of 10...
December 5, 2018: Journal of Biological Inorganic Chemistry: JBIC
Elisa Palma, Hugo M Botelho, Goreti Ribeiro Morais, Inês Rodrigues, Isabel Cordeiro Santos, Maria Paula Cabral Campello, Paula Raposinho, Ana Belchior, Susana Sousa Gomes, Maria Fátima Araújo, Isabel Correia, Nadia Ribeiro, Sofia Gama, Filipa Mendes, António Paulo
The development of pharmacologically active compounds based on bis(thiosemicarbazones) (BTSC) and on their coordination to metal centers constitutes a promising field of research. We have recently explored this class of ligands and their Cu(II) complexes for the design of cancer theranostics agents with enhanced uptake by tumoral cells. In the present work, we expand our focus to aliphatic and aromatic BTSC Zn(II) complexes bearing piperidine/morpholine pendant arms. The new complexes ZnL1 -ZnL4 were characterized by a variety of analytical techniques, which included single-crystal X-ray crystallography for ZnL2 and ZnL3 ...
November 24, 2018: Journal of Biological Inorganic Chemistry: JBIC
José Malanho Silva, Stefano Giuntini, Linda Cerofolini, Carlos F G C Geraldes, Anjos L Macedo, Enrico Ravera, Marco Fragai, Claudio Luchinat, Vito Calderone
Partial symmetry, i.e., the presence of more than one molecule in the asymmetric unit of a crystal, is a relatively rare phenomenon in small-molecule crystallography, but is quite common in protein crystallography, where it is typically known as non-crystallographic symmetry (NCS). Several papers in literature propose molecular determinants such as crystal contacts, thermal factors, or TLS parameters as an explanation for the phenomenon of intrinsic asymmetry among molecules that are in principle equivalent...
November 23, 2018: Journal of Biological Inorganic Chemistry: JBIC
Ana Z Penezić, Jelena M Aćimović, Ivan D Pavićević, Vesna B Jovanović, Marija Takić, Ljuba M Mandić
Cys34 thiol group of human serum albumin (HSA) represents major plasma antioxidant. Its reactivity is influenced by multiple factors. The influence of fatty acids (FA; saturated, mono, and poly unsaturated acids from fish oil) binding to HSA, on copper(II) binding affinity and Cys34 thiol group accessibility/reactivity, in the presence of carbonylation agent (methylglyoxal, MG) was examined. HSA-copper(II) content, thiol group reactivity, and HSA carbonylation level were monitored spectrophotometrically. Changes in HSA were followed by fluorescence spectroscopy and native PAG electrophoresis...
November 19, 2018: Journal of Biological Inorganic Chemistry: JBIC
Lawrence Que
"In the original online publication, the Foreword was incorrectly attributed. The correct author is Lawrence Que, Jr".
November 13, 2018: Journal of Biological Inorganic Chemistry: JBIC
Paolo Ascenzi, Giovanna De Simone, Diego Sbardella, Massimo Coletta
Microperoxidase-11 (MP11) is an undecapeptide derived from horse heart cytochrome c, which is considered as a heme-protein model. Here, the reductive nitrosylation of ferric MP11 (MP11(III)) under anaerobic conditions has been investigated between pH 7.4 and 9.2, at T = 20.0 °C. At pH ≤ 7.7, NO binds reversibly to MP11(III) leading to the formation of the MP11(III)-NO complex. However, between pH 8.2 and 9.2, the addition of NO to MP11(III) leads to the formation of ferrous nitrosylated MP11(II) (MP11(II)-NO)...
November 2, 2018: Journal of Biological Inorganic Chemistry: JBIC
E André, V Derrien, P Sebban, N Assrir, E Lescop, S Bernad
Human neuroglobin (Ngb) is a hexacoordinated globin which binds some small ligands. Its function is still not well-established, even though Ngb seems to be implicated in the protection against neurodegenerative diseases. It has been shown by molecular dynamics and crystallography that ligand binding could occur thanks to a haem sliding mechanism specific to Ngb. In this paper, we studied some regions which could participate in this mechanism. We used UV-visible spectroscopy, CD and NMR to have a look on the protein structure and NMR and stopped-flow to study the ligand binding properties of the proteins...
October 25, 2018: Journal of Biological Inorganic Chemistry: JBIC
A Zając, L Dymińska, J Lorenc, S M Kaczmarek, G Leniec, M Ptak, J Hanuza
The copper phytate IP6Cu, IP6Cu2 and IP6Cu3 complexes were synthesized changing the phytate to metal mole ratio. The obtained products have been characterized by means of chemical and spectroscopic studies. Spectroscopic ATR/IR, FT-Raman, UV-Vis, EPR and magnetic measurements were carried out. The structures of these compounds have been proposed on the basis of the group theory and geometry optimization taking into account the shape and number of the bands corresponding to the stretching and bending vibrations of the phosphate group and metal-oxygen polyhedron...
October 24, 2018: Journal of Biological Inorganic Chemistry: JBIC
Stephen A Mills, Kiera E Gazica, David L Tierney
Co(II) substitution into the copper amine oxidases (CAOs) has been an effective tool for evaluating the mechanism of oxygen reduction in these enzymes. However, formation of hydrogen peroxide during turnover raises questions about the relevant oxidation state of the cobalt in these enzymes and, therefore, the interpretation of the activity of the metal-substituted enzyme with respect to its mechanism of action. In this study, Co(II) was incorporated into the CAO from Hansenula polymorpha (HPAO). The effect of hydrogen peroxide on the catalytic activity of cobalt-substituted HPAO was evaluated...
October 23, 2018: Journal of Biological Inorganic Chemistry: JBIC
Fengshou Wu, Mengqian Yang, Juan Zhang, Sizhe Zhu, Mengge Shi, Kai Wang
Photodynamic therapy (PDT) is a promising cancer treatment approach with the advantages of low toxicity and noninvasive characteristics. In this study, a series of metalloporphyrin-indomethacin conjugates tethered with poly(ethylene glycol) (PEG) chains were prepared and characterized. The singlet oxygen production of the conjugates was evaluated through 2', 7'-dichlorofluorescin (DCFH) method. Because of the heavy atom effect, the metal porphyrin complexes exhibited the higher singlet oxygen (1 O2 ) quantum yield than that of free base porphyrin...
October 22, 2018: Journal of Biological Inorganic Chemistry: JBIC
Sidhali U Parsekar, Joseph Fernandes, Arnab Banerjee, Om Prakash Chouhan, Sumit Biswas, Manohar Singh, Durga P Mishra, Manjuri Kumar
We report the biological activity of three Cu(II) complexes [Cu(pabt)Cl] (1), [Cu(pma)Cl] (2), and [Cu(pdta)Cl]Cl (3) (pabt = N-(2-mercaptophenyl)-2'-pyridylmethylenimine, pma = N-(2-pyridylmethyl)-2-mercaptoaniline, pdta = 2,2'-di(pyridyl-2-methyleneimine)diphenyl disulfide). 1-3 display four-line EPR multiplet in solution at RT suggesting that these are mononuclear. DNA-binding studies using spectrophotometric titration of these complexes with calf thymus DNA showed binding through intercalation mode which was found to be consistent with the observation of increased viscosity of DNA and quenching of fluorescence of ethidium bromide bound DNA in the presence of these complexes...
December 2018: Journal of Biological Inorganic Chemistry: JBIC
Chris A E M Spronk, Szymon Żerko, Michał Górka, Wiktor Koźmiński, Benjamin Bardiaux, Barbara Zambelli, Francesco Musiani, Mario Piccioli, Priyanka Basak, Faith C Blum, Ryan C Johnson, Heidi Hu, D Scott Merrell, Michael Maroney, Stefano Ciurli
Helicobacter pylori HypA (HpHypA) is a metallochaperone necessary for maturation of [Ni,Fe]-hydrogenase and urease, the enzymes required for colonization and survival of H. pylori in the gastric mucosa. HpHypA contains a structural Zn(II) site and a unique Ni(II) binding site at the N-terminus. X-ray absorption spectra suggested that the Zn(II) coordination depends on pH and on the presence of Ni(II). This study was performed to investigate the structural properties of HpHypA as a function of pH and Ni(II) binding, using NMR spectroscopy combined with DFT and molecular dynamics calculations...
December 2018: Journal of Biological Inorganic Chemistry: JBIC
Gonzalo Scalese, Ignacio Machado, Carolina Fontana, Gastón Risi, Gustavo Salinas, Leticia Pérez-Díaz, Dinorah Gambino
Searching for prospective vanadium-based agents against Trypanosoma cruzi, the parasite causing Chagas disease, four new [VV O(8HQ-H)(L-2H)] compounds, where 8HQ is 8-hydroxyquinoline and L are tridentate salicylaldehyde semicarbazone derivatives L1-L4, were synthesized and characterized in the solid state and in solution. The compounds were evaluated on T. cruzi epimastigotes (CL Brener) as well as on VERO cells, as mammalian cell model. Compounds showed activity against T. cruzi (IC50 6.2-10.5 μM) of the same order than Nifurtimox and 8HQ, and a four- to sevenfold activity increase with respect to the free semicarbazones...
December 2018: Journal of Biological Inorganic Chemistry: JBIC
Sriramya Garapati, William Monteith, Chris Wilson, Anastasiia Kostenko, John M Kenney, Allison S Danell, Colin S Burns
Prothymosin-α is a small, multifunctional intrinsically disordered protein associated with cell survival and proliferation which binds multiple Zn2+ ions and undergoes partial folding. The interaction between prothymosin-α and at least two of its protein targets is significantly enhanced in the presence of Zn2+ ions, suggesting that Zn2+ binding plays a role in the protein's function. The primary sequence of prothymosin-α is highly acidic, with almost 50% comprised of Asp and Glu, and is unusual for a Zn2+ -binding protein as it lacks Cys and His residues...
December 2018: Journal of Biological Inorganic Chemistry: JBIC
Geng Dong, Ulf Ryde
Formate dehydrogenases (FDHs) are metalloenzymes that catalyse the reversible conversion of formate to carbon dioxide. Since such a process may be used to combat the greenhouse effect, FDHs have been extensively studied by experimental and theoretical methods. However, the reaction mechanism is still not clear; instead five putative mechanisms have been suggested. In this work, the reaction mechanism of FDH was studied by computational methods. Combined quantum mechanical and molecular mechanic (QM/MM) optimisations were performed to obtain the geometries...
December 2018: Journal of Biological Inorganic Chemistry: JBIC
Daphne S Cukierman, Elio Accardo, Rosana Garrido Gomes, Anna De Falco, Marco C Miotto, Maria Clara Ramalho Freitas, Mauricio Lanznaster, Claudio O Fernández, Nicolás A Rey
With the increasing life expectancy of the world's population, neurodegenerative diseases, such as Alzheimer's disease (AD), will become a much more relevant public health issue. This fact, coupled with the lack of efficacy of the available treatments, has been driving research directed to the development of new drugs for this pathology. Metal-protein attenuating compounds (MPACs) constitute a promising class of agents with potential application on the treatment of neurodegenerative diseases, such as AD. Currently, most MPACs are based on 8-hydroxyquinoline...
December 2018: Journal of Biological Inorganic Chemistry: JBIC
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