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Cold-adapted arsenite oxidase from a psychrotolerant Polaromonas species.

Osborne, TH; Heath, MD; Martin, AC; Pankowski, JA; Hudson-Edwards, KA; Santini, JM; (2013) Cold-adapted arsenite oxidase from a psychrotolerant Polaromonas species. Metallomics , 5 (4) 318 - 324. 10.1039/c2mt20180a. Green open access

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Abstract

Polaromonas sp. str. GM1 is an aerobic, psychrotolerant, heterotrophic member of the Betaproteobacteria and is the only isolate capable of oxidising arsenite at temperatures below 10 °C. Sequencing of the aio gene cluster in GM1 revealed the presence of the aioB and aioA genes, which encode the arsenite oxidase but the regulatory genes typically found upstream of aioB in other members of the Proteobacteria were absent. The GM1 Aio was purified to homogeneity and was found to be a heterodimer. The enzyme contained Mo and Fe as cofactors and had, using the artificial electron acceptor 2,6-dichlorophenolindophenol, a Km for arsenite of 111.70 ± 0.88 μM and a Vmax of 12.16 ± 0.30 U mg(-1), which is the highest reported specific activity for any known Aio. The temperature-activity profiles of the arsenite oxidases from GM1 and the mesophilic betaproteobacterium Alcaligenes faecalis were compared and showed that the GM1 Aio was more active at low temperatures than that of A. faecalis. A homology model of the GM1 Aio was made using the X-ray crystal structure of the Aio from A. faecalis as the template. Structural changes that account for cold adaptation were identified and it was found that these resulted in increased enzyme flexibility and a reduction in the hydrophobicity of the core.

Type: Article
Title: Cold-adapted arsenite oxidase from a psychrotolerant Polaromonas species.
Location: England
Open access status: An open access version is available from UCL Discovery
DOI: 10.1039/c2mt20180a
Publisher version: http://dx.doi.org/10.1039/c2mt20180a
Language: English
Additional information: © Royal Society of Chemistry 2014. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Keywords: Adaptation, Physiological, Betaproteobacteria, Cold Temperature, Electrophoresis, Polyacrylamide Gel, Genes, Archaeal, Models, Molecular, Multigene Family, Oxidation-Reduction, Oxidoreductases, Pseudomonas aeruginosa, Structural Homology, Protein
UCL classification: UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences > Structural and Molecular Biology
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences
URI: https://discovery.ucl.ac.uk/id/eprint/1369888
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