CATH Classification

Domain Context

CATH Clusters

Superfamily NADH Oxidase
Functional Family 5,6-dimethylbenzimidazole synthase

Enzyme Information
5,6-dimethylbenzimidazole synthase.
based on mapping to UniProt Q92PC8
FMNH(2) + NADH + O(2) = 5,6-dimethylbenzimidazole + D-erythrose 4-phosphate + NAD(+) + other product(s).
-!- The enzyme catalyzes a complex oxygen-dependent conversion of reduced flavin mononucleotide to form 5,6-dimethylbenzimidazole, the lower ligand of vitamin B12. -!- This conversion involves many sequential steps in two distinct stages, and an alloxan intermediate that acts as a proton donor, a proton acceptor, and a hydride acceptor. -!- The C-2 of 5,6-dimethylbenzimidazole is derived from C-1' of the ribityl group of FMNH(2) and 2-H from the ribityl 1'-pro-S hydrogen. -!- While D-erythrose 4-phosphate has been shown to be one of the byproducts, the nature of the other product(s) has not been verified yet. -!- Formerly EC

UniProtKB Entries (1)

Sinorhizobium meliloti 1021
5,6-dimethylbenzimidazole synthase

PDB Structure

External Links
Organism Escherichia
Primary Citation
BluB cannibalizes flavin to form the lower ligand of vitamin B12.
Taga, M.E., Larsen, N.A., Howard-Jones, A.R., Walsh, C.T., Walker, G.C.