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Journal of Biological Inorganic Chemistry: JBIC

Dinesh Kumar, Nutan Sharma, Manjula Nair
Urinary tract infections commonly occur in humans due to microbial pathogens invading the urinary tract, which can bring about a range of clinical symptoms and potentially fatal sequelae. The present study is aimed at addressing the development of a new antimicrobial agent against extended spectrum beta lactamase (ESBL) producing E. coli bacteria. We have synthesised some biologically potent (NNNN) donor macrocycles (L 1  = dibenzo[f,n]dipyrido[3,4-b:4',3'-j][1,4,9,12]tetraazacyclohexadecine-6,11,18,23(5H,12H, 7H, 24H)-tetraone, and L 2  = 6,12,19,25-tetraoxo-4,6,11,12,16,18,23,24-octahydrotetrabenzo [b,g,k,p][1,5,10,14]tetra azacyclooctadecine-2,13-dicarboxylic acid) and their Ti and Zr metal complexes in alcoholic media using microwave protocol...
January 18, 2017: Journal of Biological Inorganic Chemistry: JBIC
Kiyoshi Fujisawa
Transition metal-dioxygen complexes have fascinated bioinorganic and inorganic chemists for over half a century. The late Nobumasa Kitajima was one of the very successful researchers in this field. Despite his short career (40 years old), he made many important contributions. This Commentary highlights his important accomplishments and how they have impacted subsequent work in this area.
January 17, 2017: Journal of Biological Inorganic Chemistry: JBIC
Timothy H Yosca, Aaron P Ledray, Joanna Ngo, Michael T Green
Protonated ferryl (or iron(IV)hydroxide) intermediates have been characterized in several thiolate-ligated heme proteins that are known to catalyze C-H bond activation. The basicity of the ferryl intermediates in these species has been proposed to play a critical role in facilitating this chemistry, allowing hydrogen abstraction at reduction potentials below those that would otherwise lead to oxidative degradation of the enzyme. In this contribution, we discuss the events that led to the assignment and characterization of the unusual iron(IV)hydroxide species, highlighting experiments that provided a quantitative measure of the ferryl basicity, the iron(IV)hydroxide pKa...
January 16, 2017: Journal of Biological Inorganic Chemistry: JBIC
Yongho Kim, Binh Khanh Mai, Sumin Park
High-valent Cu and Fe species, which are generated from dioxygen activation in metalloenzymes, carry out the functionalization of strong C-H bonds. Understanding the atomic details of the catalytic mechanism has long been one of the main objectives of bioinorganic chemistry. Large H/D kinetic isotope effects (KIEs) were observed in the C-H activation by high-valent non-heme Cu or Fe complexes in enzymes and their synthetic models. The H/D KIE depends significantly on the transition state properties, such as structure, energies, frequencies, and shape of the potential energy surface, when the tunneling effect is large...
January 16, 2017: Journal of Biological Inorganic Chemistry: JBIC
Chikanobu Sugimoto, Kouta Takeda, Yumi Kariya, Hirotoshi Matsumura, Masafumi Yohda, Hiroyuki Ohno, Nobuhumi Nakamura
NAD(P)-dependent group III alcohol dehydrogenases (ADHs), well known as iron-activated enzymes, generally lose their activities under aerobic conditions due to their oxygen-sensitivities. In this paper, we expressed an extremely thermostable group III ADH from the hyperthermophilic archaeon Pyrococcus horikoshii OT3 (PhADH) heterologously in Escherichia coli. When purified from a culture medium containing nickel, the recombinant PhADH (Ni-PhADH) contained 0.85 ± 0.01 g-atoms of nickel per subunit. Ni-PhADH retained high activity under aerobic conditions (9...
January 13, 2017: Journal of Biological Inorganic Chemistry: JBIC
Yifan Wang, Jiasong Li, Aimin Liu
Molecular oxygen is utilized in numerous metabolic pathways fundamental for life. Mononuclear nonheme iron-dependent oxygenase enzymes are well known for their involvement in some of these pathways, activating O2 so that oxygen atoms can be incorporated into their primary substrates. These reactions often initiate pathways that allow organisms to use stable organic molecules as sources of carbon and energy for growth. From the myriad of reactions in which these enzymes are involved, this perspective recounts the general mechanisms of aromatic dihydroxylation and oxidative ring cleavage, both of which are ubiquitous chemical reactions found in life-sustaining processes...
January 13, 2017: Journal of Biological Inorganic Chemistry: JBIC
Yuki Okabe, Sze Koon Lee, Mio Kondo, Shigeyuki Masaoka
The construction of molecular catalysts that are active toward CO2 reduction is of great significance for designing sustainable energy conversion systems. In this study, we aimed to develop catalysts for CO2 reduction by introducing aromatic substituents to the meso-positions of iron porphyrin complexes. Three novel iron porphyrin complexes with π-expanded substituents (5,10,15,20-tetrakis(pyren-1-yl)porphyrinato iron(III) chloride (Fe-Py)), π-extended substituents (5,10,15,20-tetrakis((1,1'-biphenyl)-4-yl)porphyrinato iron(III) chloride (Fe-PPh)) and π-expanded and extended substituents (5,10,15,20-tetrakis(4-(pyren-1-yl)phenyl)porphyrinato iron(III) chloride (Fe-PPy)) were successfully synthesized, and their physical properties were investigated by UV-vis absorption spectroscopy and electrochemical measurements under Ar in comparison with an iron complex with a basic framework, 5,10,15,20-tetrakis(phenyl)porphyrinato iron(III) chloride (Fe-Ph)...
January 12, 2017: Journal of Biological Inorganic Chemistry: JBIC
Masafumi Minoshima, Kazuya Kikuchi
Super-resolution fluorescence microscopy is a recently developed imaging tool for biological researches. Several methods have been developed for detection of fluorescence signals from molecules in a subdiffraction-limited area, breaking the diffraction limit of the conventional optical microscopies and allowing visualization of detailed macromolecular structures in cells. As objectives are exposed to intense laser in the optical systems, fluorophores for super-resolution microscopy must be tolerated even under severe light irradiation conditions...
January 12, 2017: Journal of Biological Inorganic Chemistry: JBIC
V Calderone, M Fragai, G Gallo, C Luchinat
The X-ray structure of human apo-S100Z has been solved and compared with that of the zebrafish calcium-bound S100Z, which is the closest in sequence. Human apo-S100A12, which shows only 43% sequence identity to human S100Z, has been used as template model to solve the crystallographic phase problem. Although a significant buried surface area between the two physiological dimers is present in the asymmetric unit of human apo-S100Z, the protein does not form the superhelical arrangement in the crystal as observed for the zebrafish calcium-bound S100Z and human calcium-bound S100A4...
January 10, 2017: Journal of Biological Inorganic Chemistry: JBIC
Subhasree Kal, Lawrence Que
The 2-His-1-carboxylate facial triad is a widely used scaffold to bind the iron center in mononuclear nonheme iron enzymes for activating dioxygen in a variety of oxidative transformations of metabolic significance. Since the 1990s, over a hundred different iron enzymes have been identified to use this platform. This structural motif consists of two histidines and the side chain carboxylate of an aspartate or a glutamate arranged in a facial array that binds iron(II) at the active site. This triad occupies one face of an iron-centered octahedron and makes the opposite face available for the coordination of O2 and, in many cases, substrate, allowing the tailoring of the iron-dioxygen chemistry to carry out a plethora of diverse reactions...
January 10, 2017: Journal of Biological Inorganic Chemistry: JBIC
Priyanka Chauhan, Sai Brinda Muralidharan, Anand Babu Velappan, Dhrubajyoti Datta, Sanjay Pratihar, Joy Debnath, Kalyan Sundar Ghosh
Protein aggregation, due to the imbalance in the concentration of Cu(2+) and Zn(2+) ions is found to be allied with various physiological disorders. Copper is known to promote the oxidative damage of β/γ-crystallins in aged eye lens and causes their aggregation leading to cataract. Therefore, synthesis of a small-molecule 'chelator' for Cu(2+) with complementary antioxidant effect will find potential applications against aggregation of β/γ-crystallins. In this paper, we have reported the synthesis of different Schiff bases and studied their Cu(2+) complexation ability (using UV-Vis, FT-IR and ESI-MS) and antioxidant activity...
January 5, 2017: Journal of Biological Inorganic Chemistry: JBIC
Hannah U Holtkamp, Stuart J Morrow, Mario Kubanik, Christian G Hartinger
Run-by-run variations are very common in capillary electrophoretic (CE) separations and cause imprecision in both the migration times and the peak areas. This makes peak and kinetic trend identification difficult and error prone. With the aim to identify suitable standards for CE separations which are compatible with the common detectors UV, ESI-MS, and ICP-MS, the Co(III) complexes [Co(en)3]Cl3, [Co(acac)3] and K[Co(EDTA)] were evaluated as internal standards in the reaction of the anticancer drug cisplatin and guanosine 5'-monophosphate as an example of a classical biological inorganic chemistry experiment...
January 2, 2017: Journal of Biological Inorganic Chemistry: JBIC
Kuheli Das, Chiranjit Patra, Chandana Sen, Amitabha Datta, Chiara Massera, Eugenio Garribba, Mohamed Salah El Fallah, Belete B Beyene, Chen-Hsiung Hung, Chittaranjan Sinha, Tulin Askun, Pinar Celikboyun, Daniel Escudero, Antonio Frontera
A new Cu(II) dinuclear complex, Cu2L2 (1) was afforded employing the potentially pentatentate Schiff base precursor H2L, a refluxed product of o-vanillin and diethylenetriamine in methanol. Complex 1 was systematically characterized by FTIR, UV-Vis, emission and EPR spectrometry. The single crystal X-ray diffraction analysis of 1 reveals that the copper atom exhibits a distorted square planar geometry, comprising two pairs of phenolato-O and imine-N donors from two different H2L ligands. The temperature dependent magnetic interpretation agrees with the existence of weak antiferromagnetic interactions between the bridging dinuclear Cu(II) ions...
December 30, 2016: Journal of Biological Inorganic Chemistry: JBIC
Felix M C He, Paul V Bernhardt
A selection of cobalt (III)/(II) macrobicyclic 'sarcophagine' (sar) cage complexes with N3S3 mixed donor sets but differing in a single apical substituent has been chosen to span a redox potential range of +150 to -150 mV vs the normal hydrogen electrode and thus acts as redox buffers in protein spectroelectrochemistry and redox potentiometry. The cobalt(III) cage complexes are all based on the same parent structure [Co(XMeN3S3sar)](3+), where X, the variable apical substituent, is -NO2, -Cl, -OH, -NH2, or -NMe 3(+) , and a methyl group occupies the opposite apical position...
December 28, 2016: Journal of Biological Inorganic Chemistry: JBIC
Vlad Martin-Diaconescu, Crisjoe A Joseph, Jodi L Boer, Scott B Mulrooney, Robert P Hausinger, Michael J Maroney
Nickel-dependent ureases are activated by a multiprotein complex that includes the GTPase UreG. Prior studies showed that nucleotide-free UreG from Klebsiella aerogenes is monomeric and binds one nickel or zinc ion with near-equivalent affinity using an undefined binding site, whereas nucleotide-free UreG from Helicobacter pylori selectively binds one zinc ion per dimer via a universally conserved Cys-Pro-His motif in each protomer. Iodoacetamide-treated K. aerogenes UreG was nearly unaffected in nickel binding compared to non-treated sample, suggesting the absence of thiolate ligands to the metal...
December 21, 2016: Journal of Biological Inorganic Chemistry: JBIC
Courtney E Wise, Job L Grant, Jose A Amaya, Steven C Ratigan, Chun H Hsieh, Olivia M Manley, Thomas M Makris
Increasing levels of energy consumption, dwindling resources, and environmental considerations have served as compelling motivations to explore renewable alternatives to petroleum-based fuels, including enzymatic routes for hydrocarbon synthesis. Phylogenetically diverse species have long been recognized to produce hydrocarbons, but many of the enzymes responsible have been identified within the past decade. The enzymatic conversion of Cn chain length fatty aldehydes (or acids) to Cn-1 hydrocarbons, alkanes or alkenes, involves a C-C scission reaction...
December 21, 2016: Journal of Biological Inorganic Chemistry: JBIC
Jebiti Haribabu, Kumaramangalam Jeyalakshmi, Yuvaraj Arun, Nattamai S P Bhuvanesh, Paramasivan Thirumalai Perumal, Ramasamy Karvembu
A series of new Ni(II) complexes containing indole-based thiosemicarbazone ligands was synthesized and characterized by elemental analyses, and UV-visible, FT-IR, (1)H & (13)C NMR and mass spectroscopic techniques. The Ni(II) complexes (1-4) bear the general formula [Ni{C10H9N2NHCSNH(R)}2] where R = hydrogen (1), 4-methyl (2), 4-phenyl (3) and 4-cyclohexyl (4). Molecular structure of ligands (L3 and L4) and complexes (2, 3 and 4) was confirmed by single crystal X-ray crystallography. Four coordinated Ni(II) complexes showed square planar geometry...
December 19, 2016: Journal of Biological Inorganic Chemistry: JBIC
David A Quist, Daniel E Diaz, Jeffrey J Liu, Kenneth D Karlin
Nature uses dioxygen as a key oxidant in the transformation of biomolecules. Among the enzymes that are utilized for these reactions are copper-containing metalloenzymes, which are responsible for important biological functions such as the regulation of neurotransmitters, dioxygen transport, and cellular respiration. Enzymatic and model system studies work in tandem in order to gain an understanding of the fundamental reductive activation of dioxygen by copper complexes. This review covers the most recent advancements in the structures, spectroscopy, and reaction mechanisms for dioxygen-activating copper proteins and relevant synthetic models thereof...
December 5, 2016: Journal of Biological Inorganic Chemistry: JBIC
William Keown, J Brannon Gary, T Daniel P Stack
A long-standing debate in the Cu-O2 field has revolved around the relevance of the Cu(III) oxidation state in biological redox processes. The proposal of Cu(III) in biology is generally challenged as no spectroscopic or structural evidence exists currently for its presence. The reaction of synthetic Cu(I) complexes with O2 at low temperature in aprotic solvents provides the opportunity to investigate and define the chemical landscape of Cu-O2 species at a small-molecule level of detail; eight different types are characterized structurally, three of which contain at least one Cu(III) center...
December 1, 2016: Journal of Biological Inorganic Chemistry: JBIC
Xiongyi Huang, John T Groves
Since our initial report in 1976, the oxygen rebound mechanism has become the consensus mechanistic feature for an expanding variety of enzymatic C-H functionalization reactions and small molecule biomimetic catalysts. For both the biotransformations and models, an initial hydrogen atom abstraction from the substrate (R-H) by high-valent iron-oxo species (Fe(n)=O) generates a substrate radical and a reduced iron hydroxide, [Fe(n-1)-OH ·R]. This caged radical pair then evolves on a complicated energy landscape through a number of reaction pathways, such as oxygen rebound to form R-OH, rebound to a non-oxygen atom affording R-X, electron transfer of the incipient radical to yield a carbocation, R(+), desaturation to form olefins, and radical cage escape...
December 1, 2016: Journal of Biological Inorganic Chemistry: JBIC
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