Investigation of direct vs. indirect involvement of the c-type cytochrome MacA in Fe(III) reduction by Geobacter sulfurreducens.

TitleInvestigation of direct vs. indirect involvement of the c-type cytochrome MacA in Fe(III) reduction by Geobacter sulfurreducens.
Publication TypeJournal Article
Year of Publication2008
AuthorsKim B-C, Lovley DR
JournalFEMS Microbiol Lett
Volume286
Issue1
Pagination39-44
Date Published2008 Sep
ISSN0378-1097
KeywordsATP-Binding Cassette Transporters, Bacterial Proteins, Cytochromes c, Ferric Compounds, Gene Expression Regulation, Bacterial, Geobacter, Oxidation-Reduction
Abstract

The electron transfer pathway to Fe(III) reduction in Geobacter sulfurreducens has been hypothesized to consist of a series of c-type cytochromes. Previous genetic studies suggested that the inner membrane-associated, c-type cytochrome, MacA, was a component of the electron transfer chain leading to Fe(III) reduction in the dissimilatory Fe(III)-reducer, G. sulfurreducens. However, investigation of the expression of OmcB, an outer-membrane c-type cytochrome demonstrated previously to be critical for optimal Fe(III) reduction, revealed that both omcB transcript and protein levels were dramatically reduced in the MacA-deficient mutant. Expression of the omcB gene in trans enabled the MacA-deficient mutant to reduce Fe(III) at a rate that was proportional to the level of omcB expression. These results suggest that MacA is not directly involved in electron transfer to Fe(III) and further confirm the importance of OmcB in Fe(III) reduction by G. sulfurreducens.

DOI10.1111/j.1574-6968.2008.01252.x
Alternate JournalFEMS Microbiol. Lett.
PubMed ID18616590