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

Journal Article · Sat Apr 01 04:00:00 EST 2006 · Journal of Inorganic Biochemistry

DOI:https://doi.org/10.1016/j.jinorgbio.2006.07.004· OSTI ID:923007

Codd, Rachel; Lay, Peter A; Tsibakhashvili, Nelly Ya; Kalabegishvili, Tamaz L; Murusidze, Ivane G; Holman, Hoi-Ying N

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.

• Research Organization: Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 923007
• Report Number(s): LBNL--61264; BnR: YN0100000
• Journal Information: Journal of Inorganic Biochemistry, Journal Name: Journal of Inorganic Biochemistry Journal Issue: 11 Vol. 100; ISSN JIBIDJ; ISSN 0162-0134
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ALKOXIDES
BACTERIA
CARBOHYDRATES
CELL WALL
COUPLING CONSTANTS
Chromium(V) Electron paramagnetic resonance Simulation analysisArthrobacter oxydans
ELECTRON SPIN RESONANCE
FUNCTIONALS
GLYCOLS
PROTONS
SIMULATION
SPECTRA
SPECTROSCOPY