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Title: Chromium(V) complexes generated in Arthrobacter oxydans bysimulation analysis of EPR spectra

Abstract

Chromium(V) is an intermediate formed during the reductionof Cr(VI) to Cr(III) compounds by various bacteria. However, little isknown about the nature, localization and reactivity of Cr(V) species inmicrobial systems. Electron paramagnetic resonance (EPR) spectroscopy wasused to study the nature of Cr(V) complexes generated inbasalt-inhabiting Gram-positive Arthrobacter oxydans bacteria afterexposure to high concentrations of Cr(VI). Numerical simulations of theEPR spectroscopic data provide strong evidence for at least two differentdiolato-type oxoCr(V) complexes (I, giso = 1.9801; II, giso = 1.9796)involving bacterial cell wall macromolecules in the Cr(VI) A. oxydanssystem. The relative concentrations of the two oxoCr(V) diolato speciesdiffer when Cr(VI) is incubated with either untreated A. oxydans cells(I:II ~; 50:50) or lyophilized cells (I:II ~; 10:90). Based upon themagnitudes of the proton superhyperfine coupling constants (1H aiso) forspecies I and II, the EPR simulation model is unable to distinguishunambiguously whether the oxoCr(V) diolato species are linear alkoxidesor cyclic diols (carbohydrates). The oxygen-containing functional groupsassociated with teichoic acids are the most likely candidates forcomplexation with the Cr(V) ion.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
OSTI Identifier:
923007
Report Number(s):
LBNL-61264
Journal ID: ISSN 0162-0134; JIBIDJ; R&D Project: 0; BnR: YN0100000; TRN: US0801721
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Inorganic Biochemistry; Journal Volume: 100; Journal Issue: 11; Related Information: Journal Publication Date: 2006
Country of Publication:
United States
Language:
English
Subject:
54; ALKOXIDES; BACTERIA; CARBOHYDRATES; CELL WALL; COUPLING CONSTANTS; ELECTRON SPIN RESONANCE; FUNCTIONALS; GLYCOLS; PROTONS; SIMULATION; SPECTRA; SPECTROSCOPY; Chromium(V) Electron paramagnetic resonance Simulation analysisArthrobacter oxydans

Citation Formats

Codd, Rachel, Lay, Peter A., Tsibakhashvili, Nelly Ya., Kalabegishvili, Tamaz L., Murusidze, Ivane G., and Holman, Hoi-Ying N. Chromium(V) complexes generated in Arthrobacter oxydans bysimulation analysis of EPR spectra. United States: N. p., 2006. Web. doi:10.1016/j.jinorgbio.2006.07.004.
Codd, Rachel, Lay, Peter A., Tsibakhashvili, Nelly Ya., Kalabegishvili, Tamaz L., Murusidze, Ivane G., & Holman, Hoi-Ying N. Chromium(V) complexes generated in Arthrobacter oxydans bysimulation analysis of EPR spectra. United States. doi:10.1016/j.jinorgbio.2006.07.004.
Codd, Rachel, Lay, Peter A., Tsibakhashvili, Nelly Ya., Kalabegishvili, Tamaz L., Murusidze, Ivane G., and Holman, Hoi-Ying N. Sat . "Chromium(V) complexes generated in Arthrobacter oxydans bysimulation analysis of EPR spectra". United States. doi:10.1016/j.jinorgbio.2006.07.004.
@article{osti_923007,
title = {Chromium(V) complexes generated in Arthrobacter oxydans bysimulation analysis of EPR spectra},
author = {Codd, Rachel and Lay, Peter A. and Tsibakhashvili, Nelly Ya. and Kalabegishvili, Tamaz L. and Murusidze, Ivane G. and Holman, Hoi-Ying N.},
abstractNote = {Chromium(V) is an intermediate formed during the reductionof Cr(VI) to Cr(III) compounds by various bacteria. However, little isknown about the nature, localization and reactivity of Cr(V) species inmicrobial systems. Electron paramagnetic resonance (EPR) spectroscopy wasused to study the nature of Cr(V) complexes generated inbasalt-inhabiting Gram-positive Arthrobacter oxydans bacteria afterexposure to high concentrations of Cr(VI). Numerical simulations of theEPR spectroscopic data provide strong evidence for at least two differentdiolato-type oxoCr(V) complexes (I, giso = 1.9801; II, giso = 1.9796)involving bacterial cell wall macromolecules in the Cr(VI) A. oxydanssystem. The relative concentrations of the two oxoCr(V) diolato speciesdiffer when Cr(VI) is incubated with either untreated A. oxydans cells(I:II ~; 50:50) or lyophilized cells (I:II ~; 10:90). Based upon themagnitudes of the proton superhyperfine coupling constants (1H aiso) forspecies I and II, the EPR simulation model is unable to distinguishunambiguously whether the oxoCr(V) diolato species are linear alkoxidesor cyclic diols (carbohydrates). The oxygen-containing functional groupsassociated with teichoic acids are the most likely candidates forcomplexation with the Cr(V) ion.},
doi = {10.1016/j.jinorgbio.2006.07.004},
journal = {Journal of Inorganic Biochemistry},
number = 11,
volume = 100,
place = {United States},
year = {Sat Apr 01 00:00:00 EST 2006},
month = {Sat Apr 01 00:00:00 EST 2006}
}
  • The preparation, single-crystal x-ray structures, variable-temperature magnetic susceptibility, and novel EPR data are presented for two mixed-valence Mn{sup II}Mn{sup III} complexes. (Mn{sub 2}(bpmp)({mu}-OAc){sub 2})(ClO{sub 4}){sub 2}{center dot}H{sub 2}O, where bpmp{sup {minus}} is the monoanion of 2,6-bis(bis(2-pyridylmethyl)aminomethyl)-4-methylphenol, crystallizes in the monoclinic space group P2{sub 1}/n with a = 12.493 (1) {angstrom}, b = 21.583 (2) {angstrom}, c = 16.631 (2) {angstrom}, {beta} = 95.31 (1){degree}, Z = 4; R{sub F} = 0.061 and R{sub wF} = 0.085 for 4298 unique reflections (I > 3{sigma}(I)) at 297 (1) K. (Mn{sub 2}(bcmp)({mu}-OAc){sub 2})(ClO{sup {minus}}{sub 4}){sub 2}{center dot}CH{sub 2}Cl{sub 2}, where bcmp{sup {minus}} ismore » the monoanion of 2,6-bis(1,4,67-triazacyclonon-l-ylmethyl)-4-methylphenol, crystallizes in the orthorhombic space group Pca2{sub 1} with a = 19.273 (1) {angstrom}, b = 15.155 (1) {angstrom}, c = 13.749 (3) {angstrom}, Z = 4; R{sub F} = 0.074 and R{sub wF} = 0.085 for 2324 unique reflections (I > 3{sigma}(I)) at 296 (1) K.« less
  • No abstract prepared.
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