Editor's Summary
22 March 2007
The long road to vitamin B12
Vitamin B12 (cobalamin) is one of the largest known non-polymeric natural products, and it is the only vitamin that is synthesized exclusively by microorganisms. Despite years of study, the biosynthesis of one part of the vitamin is poorly understood. Now the last unknown step in its biosynthesis is revealed. The X-ray crystal structure of BluB, an enzyme that uses molecular oxygen to cleave a flavin mononucleotide cofactor to form the lower ligand of vitamin B12, has been determined. This reaction is an example of an unusual process, the enzymatic destruction of one cofactor to synthesize another.
News and Views: Biochemistry: Molecular cannibalism
The biosynthesis of vitamin B12 has fascinated generations of scientists, but part of the pathway was unknown. The missing enzymatic link has now been found, only to raise more mechanistic questions.
Steven E. Ealick & Tadhg P. Begley
doi:10.1038/446387a
Letter: BluB cannibalizes flavin to form the lower ligand of vitamin B12
Michiko E. Taga, Nicholas A. Larsen, Annaleise R. Howard-Jones, Christopher T. Walsh & Graham C. Walker
doi:10.1038/nature05611
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