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Volume 1 (2005), Issue 6, Pages 375-384
Research Article

Role of the precorrin 6-X reductase gene in cobamide biosynthesis in Methanococcus maripaludis

1Department of Microbiology, The Ohio State University, Columbus, OH, USA
2Department of Microbiology, University of Georgia, Athens, GA 30602-2605, USA

Received 4 January 2005; Accepted 25 April 2005

Copyright © 2005 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In Methanococcus maripaludis strain JJ, deletion of the homolog to cbiJ, which encodes the corrin biosynthetic enzyme precorrin 6-X reductase, yielded an auxotroph that required either cobamide or acetate for good growth. This phenotype closely resembled that of JJ117, a mutant in which tandem repeats were introduced into the region immediately downstream of the homolog of cbiJ. Mutant JJ117 also produced low quantities of cobamides, about 15 nmol g–1 protein or 1–2% of the amount found in wild-type cells. These results confirm the role of the cbiJ homolog in cobamide biosynthesis in the Archaea and suggest the presence of low amounts of a bypass activity in these organisms.