Publication
Title
The homopentameric chlorite dismutase from Magnetospirillum sp.
Author
Abstract
Chlorite dismutase (Cld) is a b-type heme containing enzyme that catalyzes the reduction of chlorite into chloride plus dioxygen. This enzyme has gained attention because it can be used in the development of bioremediation processes, biosensors, and controlled dioxygen production. In the present work, Cld was purified from Magnetospirillum sp. cells cultured anaerobically with acetate/perchlorate until stationary phase. Biochemical, spectroscopic and X-ray crystallography methods showed that Cld from Magnetospirillum sp. is a similar to 140 kDa homopentamer comprising similar to 27.8 kDa monomers. Preliminary X-ray crystallography studies confirmed the quaternary structure and the presence of one b-type heme per monomer. The EPR spectroscopic signature of the as-purified Cld samples is affected by the buffer composition used during the purification. Potassium phosphate buffer is the only buffer that affected neither the spectral nor the kinetic properties of Cld. Kinetic studies in solution revealed that Cld from Magnetospirillum sp. decomposes chlorite at high turnover rates with optimal pH 6.0. A temperature below 10 degrees C is required to avoid enzyme inactivation due to cofactor bleaching during turnover, and to achieve full substrate consumption. Cld kinetic parameters were not affected when kinetic assays were performed in the presence of air or under argon atmosphere, but chloride is a weak mixed inhibitor that modifies the EPR signal of as-prepared samples. (C) 2015 Elsevier Inc. All rights reserved.
Language
English
Source (journal)
Journal of inorganic biochemistry. - New York, N.Y.
Publication
New York, N.Y. : 2015
ISSN
0162-0134
Volume/pages
151(2015), p. 1-9
ISI
000367421100001
Full text (Publisher's DOI)
Full text (open access)
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UAntwerpen
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Publication type
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Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
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Creation 16.02.2016
Last edited 26.07.2017
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