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Journal of Inorganic Biochemistry

Xue-Wei Zhang, Shi-Lu Chen
The initial step of methanogenesis is the fixation of CO2 to formyl-methanofuran (formyl-MFR) catalyzed by formyl-MFR dehydrogenase, which can be divided into two half reactions. Herein, the second half reaction catalyzed by FwdA (formyl-methanofuran dehydrogenase subunit A), i.e., from formate to formyl-methanofuran, has been investigated using density functional theory and a chemical model based on the X-ray crystal structure. The calculations indicate that, compared with other well-known di-zinc hydrolases, the FwdA reaction employs a reverse mechanism, including the nucleophilic attack of MFR amine on formate carbon leading to a tetrahedral gem-diolate intermediate, two steps of proton transfer from amine to formate moieties assisted by the Asp385, and the CO bond dissociation to form the formyl-MFR product...
May 11, 2018: Journal of Inorganic Biochemistry
Nuria A Illán-Cabeza, Sonia B Jiménez-Pulido, Francisco Hueso-Ureña, María J Ramírez-Expósito, Purificación Sánchez-Sánchez, José M Martínez-Martos, Miguel N Moreno-Carretero
A series of Ni(II), Zn(II) and Cd(II) complexes with the Schiff base derived from the condensation 1:1 from pyridine-2-carboxaldehyde and 5,6-diamino-1,3-dimethyluracil (6-amino-1,3-dimethyl-5-[(pyridin-2-ylmethylidene)-amino]pyrimidine-2,4(1H,3H)-dione, DAAUPic) were synthesized and subsequently characterized by means of elemental analysis, FT-IR, NMR and nine of them by X-ray diffraction. Except the [Zn(μ-O,O'-AcO)(N5 ,N6 ,N1F -DAAUPicH-1 )]2 and [Cd(O,O'-NO3 )(μ-O4 ,(N5 ,N6 ,N1F )-DAAUPicH-1 )(H2 O)]2 ·2H2 O dimers and the [Cd(μ-S,N-SCN)(N5 ,N6 ,N1F -DAAUPicH-1 )]n chain-like polymer, all of them display monomeric molecular structures...
May 9, 2018: Journal of Inorganic Biochemistry
Clara Brieke, Miroslaw Tarnawski, Anja Greule, Max J Cryle
Cytochrome P450 enzymes perform an impressive range of oxidation reactions against diverse substrate scaffolds whilst generally maintaining a conserved tertiary structure and active site chemistry. Within secondary metabolism, P450 enzymes play widespread and important roles in performing crucial modifications of precursor molecules, with one example of the importance of such reactions being found in the biosynthesis of the glycopeptide antibiotics (GPAs). In GPA biosynthesis P450s, known as Oxy enzymes, are key players in the cyclization of the linear GPA peptide precursor, which is a process that is both essential for their antibiotic activity and is the source of the synthetic challenge of these important antibiotics...
May 3, 2018: Journal of Inorganic Biochemistry
Guo-Lan Ma, Xu-Dan Bi, Feng Gao, Zheng Feng, Dong-Chun Zhao, Feng-Jie Lin, Ru Yan, Dandan Liu, Peng Liu, Jingbo Chen, Hongbin Zhang
Six novel polypyridyl ruthenium complexes with (E)-2-styryl-1H- imidazo[4,5-f][1,10]phenanthroline ligand and its analogues have been designed to enhance the DNA intercalation ability of their model compound [Ru(bpy)2 (pip)]2+ (bpy = 2,2'-bipyridine, pip = 2-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline). As shown in the optimized geometry of the complexes, the introduction of styryl group not only extended the conjugated area of the intercalative ligand, but also retained the excellent planarity. These two merits have been proven to be beneficial for their DNA intercalation, thus greatly improved their inhibition activity towards DNA transcription by RNA polymerase and DNA topoisomerase, two enzymes closely related to both DNA and tumor cell growth...
May 2, 2018: Journal of Inorganic Biochemistry
Chandni Pathak, Dharmendra Kumar, Manoj Kumar Gangwar, Darshan Mhatre, Thierry Roisnel, Prasenjit Ghosh
Heterodinuclear mixed valence [Zn(II)-Fe(III)] and the homodinuclear [Zn(II)-Zn(II)] and [Ni(II)-Ni(II)] complexes of a bicompartmental ligand containing a bridging phenoxy as a O-donor and four pyridyl moieties and two amine moieties as the N-donors exhibit phosphoester hydrolysis activity similar to the hydrolase family of enzymes. While the heterodinuclear [Zn(II)-Fe(III)] (2) complex was obtained by the sequential addition of Fe(NO3 )3 ∙9H2 O and Zn(OAc)2 ∙2H2 O to the ligand 2,6‑bis{[bis(2‑pyridylmethyl)amino]methyl}‑4‑t‑butylphenol (HL) (1) in moderate yield of 37%, the homodinuclear [Zn(II)-Zn(II)] (3) and [Ni(II)-Ni(II)] (4) complexes were obtained by the direct reaction of the ligand (1) with Zn(OAc)2 ∙2H2 O and Ni(OAc)2 ∙2H2 O respectively, in good to moderate yields (43-63%)...
April 30, 2018: Journal of Inorganic Biochemistry
Yuting Yang, Weishu Bu, Sangchoul Im, Jennifer Meagher, Jeanne Stuckey, Lucy Waskell
No abstract text is available yet for this article.
April 30, 2018: Journal of Inorganic Biochemistry
Matthew Blahut, Stephen Dzul, Suning Wang, Ashoka Kandegedara, Nicholas E Grossoehme, Timothy Stemmler, F Wayne Outten
Transition metal homeostasis is necessary to sustain life. First row transition metals act as cofactors within the cell, performing vital functions ranging from DNA repair to respiration. However, intracellular metal concentrations exceeding physiological requirements may be toxic. In E. coli, the YqjH flavoprotein is thought to play a role in iron homeostasis. YqjH is transcriptionally regulated by the ferric uptake regulator and a newly discovered regulator encoded by yqjI. The apo-form of YqjI is a transcriptional repressor of both the yqjH and yqjI genes...
April 26, 2018: Journal of Inorganic Biochemistry
Carlos Sanchez-Cano, Isolda Romero-Canelón, Kalotina Geraki, Peter J Sadler
Microfocus synchrotron x-ray fluorescence (SXRF) imaging focussed on detection of the Os LIII edge shows that the organo‑osmium metallodrug candidate [(ŋ6 -p-cym)Os(Azpy-NMe2 )I]+ (p-cym = p-cymene, Azpy-NMe2  = 2-(p-([dimethylamino]phenylazo)pyridine)) [1] penetrates efficiently into the interior of A2780 human ovarian cancer cell spheroids, a model for a solid tumour. The accompanying changes in Zn and Ca distribution suggest that the complex causes nuclear damage and initiates signalling events for cell death, consistent with findings for cultured cancer cell monolayers...
April 25, 2018: Journal of Inorganic Biochemistry
Jungang Deng, Jun Wang, MuhammadHamid Khan, Ping Yu, Feng Yang, Hong Liang
We synthesized and validated five Schiff base Pt(II) complexes derived from 2-hydroxy-1-naphthaldehyde benzoyl hydrazone and its derivatives, which are modified at the benzohydrazide structures (L1-L5). The complexes were [Pt(L1)(DMSO)Cl] (C1), [Pt(L2)(DMSO)Cl] (C2), [Pt(L3)(DMSO)Cl] (C3), [Pt(L4)(DMSO)Cl] (C4), and [Pt(L5)(DMSO)Cl] (C5). Crystal structures showed that the Pt centers of all complexes were tetra-coordinated with other atoms. The structure-activity relationships and anticancer mechanisms of the complexes were explored...
April 25, 2018: Journal of Inorganic Biochemistry
Rosa A Luirink, Stefan J Dekker, Luigi Capoferri, Laura F H Janssen, Cynthia L Kuiper, Mehmet E Ari, Nico P E Vermeulen, J Chris Vos, Jan N M Commandeur, Daan P Geerke
The 5'-hydroxymethyl metabolite of the penicillin based antibiotic flucloxacillin (FLX) is considered to be involved in bile duct damage occurring in a small number of patients. Because 5'-hydroxymethyl FLX is difficult to obtain by organic synthesis, biosynthesis using highly active and regioselective biocatalysts would be an alternative approach. By screening an in-house library of Cytochrome P450 (CYP) BM3 mutants, mutant M11 L437E was identified as a regioselective enzyme with relatively high activity in production of 5'-hydroxymethyl FLX as was confirmed by mass spectrometry and NMR...
April 24, 2018: Journal of Inorganic Biochemistry
B D Ostojić, P Schwerdtfeger, D S Đorđević
The binding of hydrogen sulfide to a model heme compound is investigated by coupled-cluster singles-doubles augmented by a perturbative triple excitations, CCSD(T), and density functional theory, DFT. The minimum energy path for the H2 S addition to an isolated heme center of the heme protein is evaluated by adopting as a model the heme compound FeP(Im) (P = porphyrin; Im = imidazole). The FeP(Im)-H2 S aduct is bound by 13.7 kcal/mol at the CCSD(T) level of theory. Relaxed potential energy curves for the lowest lying spin states of the H2 S to FeP(Im) binding using DFT reveal that the binding process is associated with a "double spin-crossover" reaction with the existence of long-distance van der Waals minima only 5-7 kcal/mol above the FeP(Im)-H2 S ground state...
April 21, 2018: Journal of Inorganic Biochemistry
Misaki Nakai, Jihne Pan, Kuo-Shyan Lin, John R Thompson, Alessio Nocentini, Claudiu T Supuran, Yasuo Nakabayashi, Tim Storr
With the aim to prepare hypoxia tumor imaging agents, technetium(I) and rhenium(I) tricarbonyl complexes with dipyridylamine (L1 = N-{[1-(2,2-dioxido-1,2-benzoxathiin-6-yl)-1H-1,2,3-triazol-4-yl]methyl}-N-(2-pyridinylmethyl)-2-pyridinemethanamine; L3 = N-{[1-[N-(4-aminosulfonylphenyl)]-1H-1,2,3-triazol-4-yl]methyl}-N-(2-pyridinyl-methyl)-2-pyridinemethanamine), and iminodiacetate (H2 L2 = N-{[1-(2,2-dioxido-1,2-benzoxathiin-6-yl)-1H-1,2,3-triazole-4-yl]methyl}-N-(carboxy-methyl)-glycine; H2 L4 = N-{[1-[N-(4-aminosulfonylphenyl)]-1H-1,2,3-triazole-4-yl]methyl}-N-(carboxymethyl)-glycine) ligands appended to sulfonamide or sulfocoumarin carbonic anhydrase inhibitors were synthesized...
April 13, 2018: Journal of Inorganic Biochemistry
Joshua A Olive, J A Cowan
Iron‑sulfur clusters are essential cofactors found across all domains of life. Their assembly and transfer are accomplished by highly conserved protein complexes and partners. In eukaryotes a [2Fe-2S] cluster is first assembled in the mitochondria on the iron‑sulfur cluster scaffold protein ISCU in tandem with iron, sulfide, and electron donors. Current models suggest that a chaperone pair interacts with a cluster-bound ISCU to facilitate cluster transfer to a monothiol glutaredoxin. In humans this protein is glutaredoxin 5 (GLRX5) and the cluster can then be exchanged with a variety of target apo proteins...
April 11, 2018: Journal of Inorganic Biochemistry
Batoul Srour, Marc J F Strampraad, Wilfred R Hagen, Peter-Leon Hagedoorn
The study of the structure, function, folding and conformational transitions of cytochrome c is of great interest because this protein plays an important role in biological electron transport and apoptosis. The different native and non-native conformations have been studied extensively under equilibrium conditions at different pH values, however, kinetic studies are rare because they require technically challenging rapid mixing and spectroscopic monitoring techniques. Here we present the refolding kinetics of acid denatured cytochrome c using the pH jump technique from pH 2 to pH 4...
April 11, 2018: Journal of Inorganic Biochemistry
Jaroslaw Piskorz, Dariusz T Mlynarczyk, Wojciech Szczolko, Krystyna Konopka, Nejat Düzgüneş, Jadwiga Mielcarek
Photodynamic therapy of cancer comprises the activation of photosensitizer molecules delivered to cancer cells, to generate reactive oxygen species that mediate cytotoxicity. In this study, previously synthesized dendritic magnesium tribenzoporphyrazines were incorporated into four types of liposomes containing either 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) or 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) as the zwitterionic lipids. The addition of either l-α-phosphatidyl-dl-glycerol (PG) or 1,2-dioleoyl-3-trimethylammoniumpropane (DOTAP) imparted a negative or positive charge, respectively...
April 9, 2018: Journal of Inorganic Biochemistry
William R Arnold, Austin T Weigle, Aditi Das
Phytocannabinoids have well-known cardiovascular implications. For instance, Δ9-tetrahydrocannabinol (Δ9-THC), the principal component of cannabis, induces tachycardia in humans. In order to understand the impact of phytocannabinoids on human cardiovascular health, there is a need to study the metabolism of phytocannabinoids by cardiac cytochromes p450 (CYPs). CYP2J2, the primary CYP of cardiomyocytes, is responsible for the metabolism of the endocannabinoid, anandamide (AEA), into cardioprotective epoxides (EET-EAs)...
April 7, 2018: Journal of Inorganic Biochemistry
Francisco Zarate-Perez, Jesús B Velázquez-Fernández, Gareth K Jennings, Lisa S Shock, Charles E Lyons, John C Hackett
Cytochrome P450 19 (CYP19, aromatase) catalyzes the conversion of androgens to estrogens in a sequence of three reactions that each depend on NADPH and O2 . Aromatase is a phylogenetically-ancient enzyme and its breadth of expression in other species has highlighted distinct physiological functions. In songbirds, estrogen production is required for programming the neural circuits controlling song and in the determination of sex in fish and reptiles. This work describes the expression, purification, and biophysical characterization of Aptenodytes forsteri (Emperor penguin, af) aromatase...
April 7, 2018: Journal of Inorganic Biochemistry
Shihao Chen, Gang Liu, Mengfei Long, Hui Zou, Hengmi Cui
Alpha lipoic acid (α-LA), a potent antioxidant, is protective against acute nephrotoxicity. In the present study, the attenuation of cadmium (Cd)-induced kidney injury by α-LA on was investigated in a rat model. Exposure to 50 mg/L Cd for 12 weeks increased kidney index and Cd content, malondialdehyde (MDA) levels, and histological damage to the renal cortex, and decreased the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH). Treatment with 50 mg/L Cd also damaged renal cell mitochondria and nuclei, and activated the mitochondrial apoptosis pathway, indicated by increased gene and protein expression/activation of caspase-9, caspase-3, poly ADP-ribose polymerase (PARP) and Bcl-2 adenovirus E1a nineteen kilodalton interacting protein 3 (BNIP3), and translocation of cytochrome c (cyt c), apoptosis-inducing factor (AIF), and endonuclease G (Endo G)...
April 7, 2018: Journal of Inorganic Biochemistry
R Bregier-Jarzębowska, L Łomozik, A Gąsowska
Potentiometric and NMR spectroscopic studies of the nucleotide (NucP)/polyamine (PA) system (where NucP = CDP, CTP, PA = putrescine or spermidine) revealed the formation of molecular complexes (NucP)(Hx+y )(PA) (where Hx+y  = number of protons; x - from NucP and y - from PA). Their thermodynamic parameters were determined and the modes of their interactions were proposed. The main reaction centers were found to be the protonated amine groups of polyamine (positive centers) and phosphate groups of nucleotide (negative centers)...
April 6, 2018: Journal of Inorganic Biochemistry
Hao Zhang, Ling Yang, Long-Fei Yan, Rong-Zhen Liao, Wei-Quan Tian
Metallo-β-lactamase (MβL) is a eubacterial zinc metallo-hydrolase superfamily. Despite their well-known lactamase activities, MβL family members also have the ability to catalyze phosphotriester hydrolysis with different phosphotriesterase activities. In the present study, based on crystal structure comparisons of the related MβL members, a series of models was constructed and calculated using the density functional theory (DFT) method to explore the relationship between active-site changes and phosphotriesterase activities...
April 6, 2018: Journal of Inorganic Biochemistry
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