Shewanella spp. demonstrate great variability in the use of terminal electron acceptors in anaerobic respiration; these include nitrate, fumarate, DMSO, trimethylamine oxide, sulphur compounds and metal oxides. These pathways open up possible applications in bioremediation. The wide variety of respiratory substrates for Shewanella is correlated with the evolution of several multi-haem membrane-bound, periplasmic and outer-membrane c-type cytochromes. The 21 kDa c-type cytochrome CymA of the freshwater strain Shewanella oneidensis MR-1 has an N-terminal membrane anchor and a globular tetrahaem periplasmic domain. According to sequence alignments, CymA is a member of the NapC/NirT family. This family of redox proteins is responsible for electron transfer from the quinone pool to periplasmic and outer-membrane-bound reductases. Prior investigations have shown that the absence of CymA results in loss of the ability to respire with Fe(III), fumarate and nitrate, indicating that CymA is involved in electron transfer to several terminal reductases. Here we describe the expression, purification and characterization of a soluble, truncated CymA (‘CymA). Potentiometric studies suggest that there are two pairs of haems with potentials of -175 and -261 mV and that ‘CymA is an efficient electron donor for the soluble fumarate reductase, flavocytochrome c3.
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Conference Article|
August 01 2002
The membrane-bound tetrahaem c-type cytochrome CymA interacts directly with the soluble fumarate reductase in Shewanella
C. Schwalb;
C. Schwalb
*Institute of Cell and Molecular Biology, University of Edinburgh, The King's Buildings, Mayfield Road, Edinburgh EH9 3JR, Scotland, U.K.
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S. K. Chapman;
S. K. Chapman
†Department of Chemistry, University of Edinburgh, The King's Buildings, West Mains Road, Edinburgh EH9 3JJ, Scotland, U.K.
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G. A. Reid
G. A. Reid
1
*Institute of Cell and Molecular Biology, University of Edinburgh, The King's Buildings, Mayfield Road, Edinburgh EH9 3JR, Scotland, U.K.
1To whom correspondence should be addressed (e-mail graeme.reid@ed.ac.uk)
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Publisher: Portland Press Ltd
Received:
January 27 2002
Online ISSN: 1470-8752
Print ISSN: 0300-5127
© 2002 Biochemical Society
2002
Biochem Soc Trans (2002) 30 (4): 658–662.
Article history
Received:
January 27 2002
Citation
C. Schwalb, S. K. Chapman, G. A. Reid; The membrane-bound tetrahaem c-type cytochrome CymA interacts directly with the soluble fumarate reductase in Shewanella. Biochem Soc Trans 1 August 2002; 30 (4): 658–662. doi: https://doi.org/10.1042/bst0300658
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