Respiration of metal (hydr)oxides by Shewanella and Geobacter: a key role for multihaem c-type cytochromes
Dissimilatory reduction of metal (e.g. Fe, Mn) (hydr)oxides represents a challenge for microorganisms, as their cell envelopes are impermeable to metal (hydr)oxides that are poorly soluble in water. To overcome this physical barrier, the Gram-negative bacteria Shewanella oneidensis MR-1 and Geobactersulfurreducens have developed electron transfer (ET) strategies that require multihaem c-type cytochromes (c-Cyts). In S. oneidensis MR-1, multihaem c-Cyts CymA and MtrA are believed to transfer electrons from the inner membrane quinone/quinol pool through the periplasm to the outer membrane. The type II secretion system of S. oneidensis MR-1 has been implicated in the reduction of metal (hydr)oxides, most likely by translocating decahaem c-Cyts MtrC and OmcA across outer membrane to the surface of bacterial cells where they form a protein complex. The extracellular MtrC and OmcA can directly reduce solid metal (hydr)oxides. Likewise, outer membrane multihaem c-Cyts OmcE and OmcS of G. sulfurreducens are suggested to transfer electrons from outer membrane to type IV pili that are hypothesized to relay the electrons to solid metal (hydr)oxides. Thus, multihaem c-Cyts play critical roles in S. oneidensis MR-1-and G. sulfurreducens-mediated dissimilatory reduction of solid metal (hydr)oxides by facilitating ET across the bacterial cell envelope.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 917956
- Report Number(s):
- PNNL-SA-56434; KP1501021; TRN: US200817%%1045
- Journal Information:
- Molecular Microbiology, 65(1):12-20, Vol. 65, Issue 1
- Country of Publication:
- United States
- Language:
- English
Similar Records
The Roles of Outer Membrane Cytochromes of Shewanella and Geobacter in Extracellular Electron Transfer
Mtr Extracellular Electron Transfer Pathways in Fe(III)-reducing or Fe(II)-oxidizing Bacteria: A Genomic Perspective