کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1316084 | 976421 | 2010 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Vanadium K-edge XAS studies on the native and peroxo-forms of vanadium chloroperoxidase from Curvularia inaequalis Vanadium K-edge XAS studies on the native and peroxo-forms of vanadium chloroperoxidase from Curvularia inaequalis](/preview/png/1316084.png)
Vanadium K-edge X-ray Absorption Spectra have been recorded for the native and peroxo-forms of vanadium chloroperoxidase from Curvularia inaequalis at pH 6.0. The Extended X-ray Absorption Fine Structure (EXAFS) regions provide a refinement of previously reported crystallographic data; one short V = O bond (1.54 Å) is present in both forms. For the native enzyme, the vanadium is coordinated to two other oxygen atoms at 1.69 Å, another oxygen atom at 1.93 Å and the nitrogen of an imidazole group at 2.02 Å. In the peroxo-form, the vanadium is coordinated to two other oxygen atoms at 1.67 Å, another oxygen atom at 1.88 Å and the nitrogen of an imidazole group at 1.93 Å. When combined with the available crystallographic and kinetic data, a likely interpretation of the EXAFS distances is a side-on bound peroxide involving V–O bonds of 1.67 and 1.88 Å; thus, the latter oxygen would be ‘activated’ for transfer. The shorter V–N bond observed in the peroxo-form is in line with the previously reported stronger binding of the cofactor in this form of the enzyme. Reduction of the enzyme with dithionite has a clear influence on the spectrum, showing a change from vanadium(V) to vanadium(IV).
Graphical AbstractVanadium K-edge X-ray Absorption Spectra have been recorded for the native and peroxo-forms of vanadium chloroperoxidase from Curvularia inaequalis at pH 6.0. The EXAFS regions provide a refinement of previously reported crystallographic data. The presented spectra are the first on a peroxo-intermediate of a vanadium haloperoxidase.Figure optionsDownload as PowerPoint slide
Journal: Journal of Inorganic Biochemistry - Volume 104, Issue 6, June 2010, Pages 657–664