Periplasmic electron transfer via the c-type cytochromes MtrA and FccA of Shewanella oneidensis MR-1.

TitlePeriplasmic electron transfer via the c-type cytochromes MtrA and FccA of Shewanella oneidensis MR-1.
Publication TypeJournal Article
Year of Publication2009
AuthorsSchuetz, B, Schicklberger M, Kuermann J, Spormann AM, Gescher J
JournalApplied and environmental microbiology
Date Published2009 Dec
KeywordsBacterial Outer Membrane Proteins, Cytochrome c Group, Electron Transport, Escherichia coli, Ferric Compounds, Fumarates, Gene Expression Regulation, Bacterial, Oxidation-Reduction, Periplasm, Shewanella, Succinate Dehydrogenase
AbstractDissimilatory microbial reduction of insoluble Fe(III) oxides is a geochemically and ecologically important process which involves the transfer of cellular, respiratory electrons from the cytoplasmic membrane to insoluble, extracellular, mineral-phase electron acceptors. In this paper evidence is provided for the function of the periplasmic fumarate reductase FccA and the decaheme c-type cytochrome MtrA in periplasmic electron transfer reactions in the gammaproteobacterium Shewanella oneidensis. Both proteins are abundant in the periplasm of ferric citrate-reducing S. oneidensis cells. In vitro fumarate reductase FccA and c-type cytochrome MtrA were reduced by the cytoplasmic membrane-bound protein CymA. Electron transfer between CymA and MtrA was 1.4-fold faster than the CymA-catalyzed reduction of FccA. Further experiments showing a bidirectional electron transfer between FccA and MtrA provided evidence for an electron transfer network in the periplasmic space of S. oneidensis. Hence, FccA could function in both the electron transport to fumarate and via MtrA to mineral-phase Fe(III). Growth experiments with a DeltafccA deletion mutant suggest a role of FccA as a transient electron storage protein.
Alternate JournalAppl. Environ. Microbiol.
0 November 24, 2010