Unique Biochemical and Sequence Features Enable BluB To Destroy Flavin and Distinguish BluB from the Flavin Monooxygenase Superfamily.

ABSTRACT: Vitamin B₁₂ (cobalamin) is an essential micronutrient for humans that is synthesized by only a subset of bacteria and archaea. The aerobic biosynthesis of 5,6-dimethylbenzimidazole, the lower axial ligand of cobalamin, is catalyzed by the "flavin destructase" enzyme BluB, which fragments reduced flavin mononucleotide following its reaction with oxygen to yield this ligand. BluB is similar in sequence and structure to members of the flavin oxidoreductase superfamily, yet the flavin destruction process has remained elusive. Using stopped-flow spectrophotometry, we find that the flavin destructase reaction of BluB from Sinorhizobium meliloti is initiated with canonical flavin-O₂ chemistry. A C4a-peroxyflavin intermediate is rapidly formed in BluB upon reaction with O

SUBMITTER: Hazra AB 

PROVIDER: S-EPMC6824417 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature