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Archaea, 1:375–384
© 2005 Heron Publishing—Victoria, Canada
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Role of the precorrin 6-X reductase gene in cobamide biosynthesis in Methanococcus maripaludis

Wonduck Kim (1, 2), Tiffany A. Major (2) and William B. Whitman (2, 3)

1. Department of Microbiology, The Ohio State University, Columbus, OH, USA / 2. Department of Microbiology, University of Georgia, Athens, GA 30602-2605, USA / 3. Corresponding author ([email protected]) / Received January 4, 2005; accepted April 25, 2005; published online May 25, 2005


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.

Keywords: archaea, cbiJ, vitamin B12 biosynthesis.

ISSN 1472-3654 (Online) ISSN 1472-3646 (Print) Copyright © 2002–2007 Heron Publishing