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Journal of Biological Inorganic Chemistry: JBIC

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https://www.readbyqxmd.com/read/28432454/cobalt-tetradehydrocorrins-coordinated-by-imidazolate-like-histidine-in-the-heme-pocket-of-horseradish-peroxidase
#1
Koji Oohora, Ning Tang, Yoshitsugu Morita, Takashi Hayashi
Horseradish peroxidase was reconstituted with cobalt tetradehydrocorrin, rHRP(Co(TDHC)), as a structural analog of cobalamin coordinated with an imidazolate-like His residue, which is generally seen in native enzymes. In contrast to the previously reported cobalt tetradehydrocorrin-reconstituted myoglobin, rMb(Co(TDHC)), the HRP matrix was expected to provide strong axial ligation by His170 which has imidazolate character. rHRP(Co(II)(TDHC)) was characterized by EPR and its reaction with reductants indicates a negative shift of its redox potential compared to rMb(Co(TDHC))...
April 21, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28432453/the-influence-of-oxo-bridged-binuclear-gold-iii-complexes-on-na-k-atpase-activity-a-joint-experimental-and-theoretical-approach
#2
Aleksandra M Bondžić, Mirjana B Čolović, Goran V Janjić, Božidarka Zarić, Sandra Petrović, Danijela Z Krstić, Tiziano Marzo, Luigi Messori, Vesna M Vasić
The in vitro effects of oxo-bridged binuclear gold(III) complexes, i.e., [(bipy2Me)2Au2(μ-O)2][PF6]2 (Auoxo6), Au2[(bipydmb-H)2(μ-O)][PF6] (Au2bipyC) and [Au2(phen(2Me))2(μ-O)2](PF6)2 (Au2phen) on Na/K-ATPase, purified from the porcine cerebral cortex, were investigated. All three studied gold complexes inhibited the enzyme activity in a concentration-dependent manner achieving IC50 values in the low micromolar range. Kinetic analysis suggested an uncompetitive mode of inhibition for Auoxo6 and Au2bipyC, and a mixed type one for Au2phen...
April 21, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28421385/in-vitro-and-in-vivo-anti-tumor-effects-of-selected-platinum-iv-and-dinuclear-platinum-ii-complexes-against-lung-cancer-cells
#3
Milos Arsenijevic, Marija Milovanovic, Snezana Jovanovic, Natalija Arsenijevic, Bojana Simovic Markovic, Marina Gazdic, Vladislav Volarevic
In the present study, cytotoxic effects of cisplatin, the most usually used chemotherapeutic agent, were compared with new designed platinum(IV) ([PtCl4(en)] (en = ethylenediamine) and [PtCl4(dach)]) (dach = (±)-trans-1,2-diaminocyclohexane) and platinum(II) complexes ([{trans-Pt(NH3)2Cl}2(μ-pyrazine)](ClO4)2 (Pt1), [{trans-Pt(NH3)2Cl}2(μ-4,4'-bipyridyl)](ClO4)2DMF(Pt2),[{trans-Pt(NH3)2Cl}2(μ-1,2-bis(4pyridyl)ethane)](ClO4)2 (Pt3)), in vitro and in vivo against human and murine lung cancer cells, to determine anti-tumor potential of newly synthesized platinum-based drugs in the therapy of lung cancer...
April 18, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28405842/egfr-targeting-peptide-coupled-platinum-iv-complexes
#4
Josef Mayr, Sonja Hager, Bettina Koblmüller, Matthias H M Klose, Katharina Holste, Britta Fischer, Karla Pelivan, Walter Berger, Petra Heffeter, Christian R Kowol, Bernhard K Keppler
The high mortality rate of lung cancer patients and the frequent occurrence of side effects during cancer therapy demonstrate the need for more selective and targeted drugs. An important and well-established target for lung cancer treatment is the occasionally mutated epidermal growth factor receptor (EGFR). As platinum(II) drugs are still the most important therapeutics against lung cancer, we synthesized in this study the first platinum(IV) complexes coupled to the EGFR-targeting peptide LARLLT (and the shuffled RTALLL as reference)...
April 12, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28389830/effect-of-donor-atom-identity-on-metal-binding-pharmacophore-coordination
#5
Benjamin L Dick, Ashay Patel, J Andrew McCammon, Seth M Cohen
The inhibition and binding of three metal-binding pharmacophores (MBPs), 2-hydroxycyclohepta-2,4,6-trien-1-one (tropolone), 2-mercaptopyridine-N-oxide (1,2-HOPTO), and 2-hydroxycyclohepta-2,4,6-triene-1-thione (thiotropolone) to human carbonic anhydrase II (hCAII) and a mutant protein hCAII L198G were investigated. These MBPs displayed bidentate coordination to the active site Zn(II) metal ion, but the MBPs respond to the mutation of L198G differently, as characterized by inhibition activity assays and X-ray crystallography...
April 7, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28378164/computational-evidence-support-the-hypothesis-of-neuroglobin-also-acting-as-an-electron-transfer-species
#6
Licia Paltrinieri, Giulia Di Rocco, Gianantonio Battistuzzi, Marco Borsari, Marco Sola, Antonio Ranieri, Laura Zanetti-Polzi, Isabella Daidone, Carlo Augusto Bortolotti
Neuroglobin (Ngb) is a recently identified hexa-coordinated globin, expressed in the nervous system of humans. Its physiological role is still debated: one hypothesis is that Ngb serves as an electron transfer (ET) species, possibly by reducing cytochrome c and preventing it to initiate the apoptotic cascade. Here, we use the perturbed matrix method (PMM), a mixed quantum mechanics/molecular dynamics approach, to investigate the redox thermodynamics of two neuroglobins, namely the human Ngb and GLB-6 from invertebrate Caenorhabditis elegans...
April 4, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28374136/high-cytotoxicity-of-vanadium-iv-complexes-with-1-10-phenanthroline-and-related-ligands-is-due-to-decomposition-in-cell-culture-medium
#7
Maria Le, Oliver Rathje, Aviva Levina, Peter A Lay
Cytotoxic effects of Metvan (cis-[V(IV)O(OSO3)(Me2phen)2], where Me2phen = 4,7-dimethyl-1,10-phenanthroline) and its analogues with 1,10-phenanthroline (phen) and 2,2'-bipyridine (bpy) ligands in cultured human lung cancer (A549) cells have been re-investigated in conjunction with reactivity of the V(IV) complexes in neutral aerated aqueous solutions and in cell culture medium. All the V(IV) complexes underwent rapid oxidation to the corresponding V(V) species (cis-[V(V)(O)2L2](+)), followed by release of free ligands (shown by electrospray mass spectrometry)...
April 3, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28364223/remarkable-reactivity-of-alkoxide-acetato-bridged-binuclear-copper-ii-complex-as-artificial-carboxylesterase
#8
Bin Xu, Weidong Jiang, Xiaoqiang Liu, Fuan Liu, Zheng Xiang
Bromo-containing binuclear Schiff base copper(II) complex, Cu2L(OAc), with an alkoxo/acetato-bridged moiety was employed as a model of carboxylesterases to promote the hydrolytic cleavage of p-nitrophenyl picolinate (PNPP). Furthermore, the reactivity of a mononuclear complex (CuHL) was evaluated for comparing it with that of binuclear one. The results reveal that the as-prepared binuclear Cu2L(OAc) efficiently accelerated the hydrolysis of PNPP, giving rise to excess four orders of magnitude rate enhancement in contrast to the un-catalyzed reaction...
March 31, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28364222/siderophores-and-mussel-foot-proteins-the-role-of-catechol-cations-and-metal-coordination-in-surface-adhesion
#9
REVIEW
Greg P Maier, Alison Butler
Metal coordination, hydrogen bonding, redox reactions, and covalent crosslinking are seemingly disparate chemical and physicochemical processes that are all accomplished in natural materials by the catechol functional group. This review focuses on the reactivity of catechols in tris-2,3-dihydroxybenzoyl-containing microbial siderophores and synthetic analogs, as well as Dopa-(3,4-dihydroxyphenylalanine)-containing mussel foot proteins that adhere to surfaces in aqueous conditions. Mussel foot proteins with a high content of Dopa and cationic amino acids, Lys and Arg, adhere strongly to mica, an aluminosilicate mineral, in aqueous conditions...
March 31, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28361362/functional-disruption-of-peroxiredoxin-by-bismuth-antiulcer-drugs-attenuates-helicobacter-pylori-survival
#10
Yuen-Yan Chang, Tianfan Cheng, Xinming Yang, Lijian Jin, Hongzhe Sun, Hongyan Li
Bismuth drugs have been used clinically to treat infections from Helicobacter pylori, a pathogen that is strongly related to gastrointestinal diseases even stomach cancer. Despite extensive studies, the mechanisms of action of bismuth drugs are not fully understood. Alkyl hydroperoxide reductase subunit C (AhpC) is the most abundant 2-cysteine peroxiredoxin, crucial for H. pylori survival in the host by defense of oxidative stress. Herein we show that a Bi(III) antiulcer drug (CBS) binds to the highly conserved cysteine residues (Cys49 and Cys169) with a dissociation constant (K d) of Bi(III) to AhpC of 3...
March 30, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28321603/similarities-and-differences-of-copper-and-zinc-cations-binding-to-biologically-relevant-peptides-studied-by-vibrational-spectroscopies
#11
Alicia Schirer, Youssef El Khoury, Peter Faller, Petra Hellwig
GHK and DAHK are biological peptides that bind both copper and zinc cations. Here we used infrared and Raman spectroscopies to study the coordination modes of both copper and zinc ions, at pH 6.8 and 8.9, correlating the data with the crystal structures that are only available for the copper-bound form. We found that Cu(II) binds to deprotonated backbone (amidate), the N-terminus and N(π) of the histidine side chain, in both GHK and DAHK, at pH 6.8 and 8.9. The data for the coordination of zinc at pH 6.8 points to two conformers including both nitrogens of a histidine residue...
March 20, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28315011/the-exocyclic-amino-group-of-adenine-in-pt-ii-and-pd-ii-complexes-a-critical-comparison-of-the-x-ray-crystallographic-structural-data-and-gas-phase-calculations
#12
Radu Silaghi-Dumitrescu, Béla Mihály, Timea Mihály, Amr A A Attia, Pablo J Sanz Miguel, Bernhard Lippert
A detailed computational (DFT level of theory) study regarding the nature of the exocyclic amino group, N6H2, of the model nucleobase 9-methyladenine (9MeA) and its protonated (9MeAH(+)) and deprotonated forms (9MeA-H), free and metal-complexed, has been conducted. The metals are Pt(II) and Pd(II), bonded to nitrogen-containing co-ligands (NH3, dien, bpy), with N1, N6, and N7 being the metal-binding sites, individually or in different combinations. The results obtained from gas phase calculations are critically compared with X-ray crystallography data, whenever possible...
March 17, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28246923/effect-of-methionine80-heme-coordination-on-domain-swapping-of-cytochrome-c
#13
Shun Hirota, Nobuhiro Yamashiro, Zhonghua Wang, Satoshi Nagao
Cytochrome c (cyt c) forms oligomers by domain swapping. It exchanges the C-terminal α-helical region between protomers, and the Met80‒heme iron bond is perturbed significantly in domain-swapped oligomers. The peroxidase activity of cyt c increases by Met80 dissociation from the heme iron, which may trigger apoptosis. This study elucidates the effect of the Met80 heme coordination on cyt c domain swapping by obtaining oligomers for both wild-type (WT) and M80A human cyt c by an addition of ethanol to their monomers, followed by lyophilization and dissolution to buffer, and investigating their dimer properties...
February 28, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28224255/thiol-oxidase-ability-of-copper-ion-is-specifically-retained-upon-chelation-by-aldose-reductase
#14
Francesco Balestri, Roberta Moschini, Mario Cappiello, Umberto Mura, Antonella Del-Corso
Bovine lens aldose reductase is susceptible to a copper-mediated oxidation, leading to the generation of a disulfide bridge with the concomitant incorporation of two equivalents of the metal and inactivation of the enzyme. The metal complexed by the protein remains redox active, being able to catalyse the oxidation of different physiological thiol compounds. The thiol oxidase activity displayed by the enzymatic form carrying one equivalent of copper ion (Cu1-AR) has been characterized. The efficacy of Cu1-AR in catalysing thiol oxidation is essentially comparable to the free copper in terms of both thiol concentration and pH effect...
February 21, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28197737/reactive-sites-and-course-of-reduction-in-the-rieske-protein
#15
Si Ying Li, Paul H Oyala, R David Britt, Susan T Weintraub, Laura M Hunsicker-Wang
Rieske proteins play an essential role in electron transfer in the bc 1 complex. Rieske proteins contain a [2Fe-2S] cluster with one iron ligated by two histidines and the other iron ligated by two cysteines. All Rieske proteins have pH-dependent reduction potentials with the histidines ligating the cluster deprotonating in response to increases in pH. The addition of diethylpyrocarbonate (DEPC) modifies deprotonated histidines. The previous studies on the isolated Thermus thermophilus Rieske protein have used large excesses of DEPC, and this study examines what amino acids become modified under different molar equivalents of DEPC to protein...
February 14, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28190114/60-years-of-dioxygen-activation
#16
EDITORIAL
Lawrence Que
No abstract text is available yet for this article.
February 11, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28175984/three-bilindione-isomers-synthesis-characterization-and-reactivity-of-biliverdin-analogs
#17
Jun-Fei Wang, Fang Ma, Hao-Ling Sun, Jing Zhang, Jun-Long Zhang
Linear tetrapyrrole is the core structure of light-sensitive native cofactors such as phycocyanobilin, phytochromobilin and bile pigments, which attracts increasing attention in biomimetic chemistry, photochemistry and coordination chemistry. To decipher the relationship between structures and functions, in this work, we firstly reported the synthesis, isolation and characterization of three bilindione isomers (ZZZ, syn, syn, syn 1, EZE, syn, syn, anti 2 and EZE, anti, syn, anti 3) bearing meso-pentafluorophenyl groups...
February 7, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28091754/a-new-look-at-the-role-of-thiolate-ligation-in-cytochrome-p450
#18
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...
April 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28084551/oxygen-activation-by-mononuclear-nonheme-iron-dioxygenases-involved-in-the-degradation-of-aromatics
#19
REVIEW
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...
April 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/27909920/beyond-ferryl-mediated-hydroxylation-40%C3%A2-years-of-the-rebound-mechanism-and-c-h-activation
#20
REVIEW
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...
April 2017: Journal of Biological Inorganic Chemistry: JBIC
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