Jump to main content
Jump to site search

Issue 4, 2013
Previous Article Next Article

Cold-adapted arsenite oxidase from a psychrotolerant Polaromonas species

Author affiliations

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.

Graphical abstract: Cold-adapted arsenite oxidase from a psychrotolerant Polaromonas species

Back to tab navigation

Supplementary files

Publication details

The article was received on 07 Sep 2012, accepted on 30 Oct 2012 and first published on 31 Oct 2012


Article type: Paper
DOI: 10.1039/C2MT20180A
Citation: Metallomics, 2013,5, 318-324
  • Open access: Creative Commons BY license
  •   Request permissions

    Cold-adapted arsenite oxidase from a psychrotolerant Polaromonas species

    T. H. Osborne, M. D. Heath, A. C. R. Martin, J. A. Pankowski, K. A. Hudson-Edwards and J. M. Santini, Metallomics, 2013, 5, 318
    DOI: 10.1039/C2MT20180A

    This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements