How are "atypical" sulfite deydrogenases linked to cell metabolism? Interactions between the SorT sulfite dehydrogenase and small redox proteins

Low, Louie, Kilmartin, James Ryan, Bernhardt, Paul V. and Kappler, Ulrike (2011) How are "atypical" sulfite deydrogenases linked to cell metabolism? Interactions between the SorT sulfite dehydrogenase and small redox proteins. Frontiers in Microbiology, 2 MAR: 58-1-58-10. doi:10.3389/fmicb.2011.00058

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Author Low, Louie
Kilmartin, James Ryan
Bernhardt, Paul V.
Kappler, Ulrike
Title How are "atypical" sulfite deydrogenases linked to cell metabolism? Interactions between the SorT sulfite dehydrogenase and small redox proteins
Journal name Frontiers in Microbiology   Check publisher's open access policy
ISSN 1664-302X
Publication date 2011-03-25
Sub-type Article (original research)
DOI 10.3389/fmicb.2011.00058
Open Access Status DOI
Volume 2
Issue MAR
Start page 58-1
End page 58-10
Total pages 10
Place of publication Lausanne, Switzerland
Publisher Frontiers Research Foundation
Collection year 2012
Language eng
Formatted abstract
Sulfite dehydrogenases (SDHs) are enzymes that catalyze the oxidation of the toxic and mutagenic compound sulfite to sulfate, thereby protecting cells from adverse effects associated with sulfite exposure. While some bacterial SDHs that have been characterized to date are able to use cytochrome c as an electron acceptor, the majority of these enzymes prefer ferricyanide as an electron acceptor and have therefore been termed “atypical” SDHs. Identifying the natural electron acceptor of these enzymes, however, is crucial for understanding how the “atypical” SDHs are integrated into cell metabolism. The SorT sulfite dehydrogenase from Sinorhizobium meliloti is a representative of this enzyme type and we have investigated the interactions of SorT with two small redox proteins, a cytochrome c and a Cu containing pseudoazurin, that are encoded in the same operon and are co-transcribed with the sorT gene. Both potential acceptor proteins have been purified and characterized in terms of their biochemical and electrochemical properties, and interactions and enzymatic studies with both the purified SorT sulfite dehydrogenase and components of the respiratory chain have been carried out. We were able to show for the first time that an “atypical” sulfite dehydrogenase can couple efficiently to a cytochrome c isolated from the same organism despite being unable to efficiently reduce horse heart cytochrome c, however, at present the role of the pseudoazurin in SorT electron transfer is unclear, but it is possible that it acts as an intermediate electron shuttle between. The SorT system appears to couple directly to the respiratory chain, most likely to a cytochrome oxidase.
Keyword Sulfite dehydrogenase
Sulfite oxidation
Moybdoenzyme
Cytochrome
Redox protein
Pseudoazurin
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes This paper is part of a special volume on bacterial sulfur metabolism.

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2012 Collection
School of Chemistry and Molecular Biosciences
 
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Created: Wed, 12 Oct 2011, 17:45:33 EST by Dr Ulrike Kappler on behalf of School of Chemistry & Molecular Biosciences