Protein
5,6-dimethylbenzimidazole synthase
Organism
Rhodospirillum rubrum (strain ATCC 11170 / ATH 1.1.1 / DSM 467 / LMG 4362 / NCIB 8255 / S1)
Function
Involved in the biosynthesis of cobalamin (vitamin B12). Catalyzes the oxidative fragmentation and contraction of the isoalloxazine heterocycle and the cleavage of the ribityl tail of FMNH(2) to form 5,6-dimethylbenzimidazole (DMB) and D-erythrose 4-phosphate (E4P). NAD(P)H is only required initially to reduce FMN and oxygen drives the oxidative fragmentation.
Similarity
Belongs to the BluB family.
Sequence
MRTGPLFDPSFRDGLDALFQWRRDVRHFRKDPIDEETVARLLACADLAPSVGNSQPWRFVRVDDGARRGVIIDDFTRCNAAARALQPEERQDAYARLKLEGLREAPLQLAVFCDEATDQGHGLGQATMPETRRYSVVMAIHTLWLAARARGLGVGWVSVLDPQTVTAALDVPAEWAFVAYLCIGWPREEHPIPELERLGWQSRRPHPVVRR