%0 Journal Article
%T The outer membrane protein Omp35 affects the reduction of Fe(III), nitrate, and fumarate by Shewanella oneidensis MR-1
%A Tamara M Maier
%A Charles R Myers
%J BMC Microbiology
%D 2004
%I BioMed Central
%R 10.1186/1471-2180-4-23
%X Omp35 was purified from the OM of anaerobically grown cells, the gene encoding Omp35 was identified, and an omp35 null mutant (OMP35-1) was isolated and characterized. Although OMP35-1 grew on all electron acceptors tested, a significant lag was seen when grown on fumarate, nitrate, and Fe(III). Complementation studies confirmed that the phenotype of OMP35-1 was due to the loss of Omp35. Despite its requirement for wild-type rates of electron acceptor use, analysis of Omp35 protein and predicted sequence did not identify any electron transport moieties or predicted motifs. OMP35-1 had normal levels and distribution of known electron transport components including quinones, cytochromes, and fumarate reductase. Omp35 is related to putative porins from MR-1 and S. frigidimarina as well as to the PorA porin from Neisseria meningitidis. Subcellular fraction analysis confirmed that Omp35 is an OM protein. The seven-fold anaerobic upregulation of Omp35 is mediated post-transcriptionally.Omp35 is a putative porin in the OM of MR-1 that is markedly upregulated anaerobically by a post-transcriptional mechanism. Omp35 is required for normal rates of growth on Fe(III), fumarate, and nitrate, but its absence has no effect on the use of other electron acceptors. Omp35 does not contain obvious electron transport moieties, and its absence does not alter the amounts or distribution of other known electron transport components including quinones and cytochromes. The effects of Omp35 on anaerobic electron acceptor use are therefore likely indirect. The results demonstrate the ability of non-electron transport proteins to influence anaerobic respiratory phenotypes.Shewanella oneidensis (formerly putrefaciens) MR-1 is a Gram-negative bacterium that can use a wide variety of terminal electron acceptors for anaerobic respiration including insoluble manganese (Mn) and iron (Fe) oxides [1-4]. Some electron transport components are common to the use of multiple electron acceptors. For exampl
%U http://www.biomedcentral.com/1471-2180/4/23