Mtr extracellular electron-transfer pathways in Fe(III)-reducing or Fe(II)-oxidizing bacteria: a genomic perspective
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- Liang Shi
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352, U.S.A.
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- Kevin M. Rosso
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352, U.S.A.
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- John M. Zachara
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352, U.S.A.
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- James K. Fredrickson
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352, U.S.A.
抄録
<jats:p>Originally discovered in the dissimilatory metal-reducing bacterium Shewanella oneidensis MR-1 (MR-1), key components of the Mtr (i.e. metal-reducing) pathway exist in all strains of metal-reducing Shewanella characterized. The protein components identified to date for the Mtr pathway of MR-1 include four multihaem c-Cyts (c-type cytochromes), CymA, MtrA, MtrC and OmcA, and a porin-like outer membrane protein MtrB. They are strategically positioned along the width of the MR-1 cell envelope to mediate electron transfer from the quinone/quinol pool in the inner membrane to Fe(III)-containing minerals external to the bacterial cells. A survey of microbial genomes has identified homologues of the Mtr pathway in other dissimilatory Fe(III)-reducing bacteria, including Aeromonas hydrophila, Ferrimonas balearica and Rhodoferax ferrireducens, and in the Fe(II)-oxidizing bacteria Dechloromonas aromatica RCB, Gallionella capsiferriformans ES-2 and Sideroxydans lithotrophicus ES-1. The apparent widespread distribution of Mtr pathways in both Fe(III)-reducing and Fe(II)-oxidizing bacteria suggests a bidirectional electron transfer role, and emphasizes the importance of this type of extracellular electron-transfer pathway in microbial redox transformation of iron. The organizational and electron-transfer characteristics of the Mtr pathways may be shared by other pathways used by micro-organisms for exchanging electrons with their extracellular environments.</jats:p>
収録刊行物
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- Biochemical Society Transactions
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Biochemical Society Transactions 40 (6), 1261-1267, 2012-11-21
Portland Press Ltd.