کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10574215 976519 2006 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Chromium(V) complexes generated in Arthrobacter oxydans by simulation analysis of EPR spectra
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی معدنی
پیش نمایش صفحه اول مقاله
Chromium(V) complexes generated in Arthrobacter oxydans by simulation analysis of EPR spectra
چکیده انگلیسی
Chromium(V) is an intermediate formed during the reduction of Cr(VI) to Cr(III) compounds by various bacteria. However, little is known about the nature, localization and reactivity of Cr(V) species in microbial systems. Electron paramagnetic resonance (EPR) spectroscopy was used to study the nature of Cr(V) complexes generated in basalt-inhabiting Gram-positive Arthrobacter oxydans bacteria after exposure to high concentrations of Cr(VI). Numerical simulations of the EPR spectroscopic data provide strong evidence for at least two different diolato-type oxoCr(V) complexes (I, giso = 1.9801; II, giso = 1.9796) involving bacterial cell wall macromolecules in the Cr(VI)-A. oxydans system. The relative concentrations of the two oxoCr(V)-diolato species differ when Cr(VI) is incubated with either untreated A. oxydans cells (I:II ∼50:50) or lyophilized cells (I:II ∼10:90). Based upon the magnitudes of the proton superhyperfine coupling constants (1H aiso) for species I and II, the EPR simulation model is unable to distinguish unambiguously whether the oxoCr(V)-diolato species are linear alkoxides or cyclic diols (carbohydrates). The oxygen-containing functional groups associated with teichoic acids are the most likely candidates for complexation with the Cr(V) ion.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Inorganic Biochemistry - Volume 100, Issue 11, November 2006, Pages 1827-1833
نویسندگان
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