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Overlapping role of the outer membrane cytochromes of Shewanella oneidensis MR-1 in the reduction of manganese(IV) oxide. Lett Appl Microbiol 2003;37(1):21-5

Date

06/14/2003

Pubmed ID

12803550

DOI

10.1046/j.1472-765x.2003.01338.x

Scopus ID

2-s2.0-0038817925 (requires institutional sign-in at Scopus site)   50 Citations

Abstract

AIM: To determine if the outer membrane (OM) cytochromes OmcA and OmcB of the metal-reducing bacterium Shewanella oneidensis MR-1 have distinct or overlapping roles in the reduction of insoluble manganese(IV) oxide.

METHODS AND RESULTS: The gene replacement mutant (OMCA1) which lacks OmcA was partially deficient in Mn(IV) reduction. Complementation of OMCA1 with a vector (pVK21) that contains omcB but not omcA restored Mn(IV) reduction to levels that were even greater than those of wild-type. Examination of the OM of OMCA1/pVK21 revealed greater than wild-type levels of OmcB protein and specific haem content.

CONCLUSIONS: Overexpression of OmcB can compensate for the absence of OmcA in the reduction of insoluble Mn(IV) oxides. Therefore, there is at least a partial overlap in the roles of these OM cytochromes in the reduction of insoluble Mn(IV) oxide.

SIGNIFICANCE: The overlapping roles of these two cytochromes has important implications for understanding the mechanism by which MR-1 reduces insoluble metal oxides. There is no obligatory sequential electron transfer from one cytochrome to the other. They could both potentially serve as terminal reductases for extracellular electron acceptors.

Author List

Myers JM, Myers CR

MESH terms used to index this publication - Major topics in bold

Anaerobiosis
Bacterial Outer Membrane Proteins
Bacterial Proteins
Blotting, Western
Cytochrome c Group
Cytochromes
Gene Deletion
Manganese Compounds
Mutation
Oxidation-Reduction
Oxides
Shewanella