ID   4.1.99.23
DE   5-hydroxybenzimidazole synthase.
AN   HBI synthase.
CA   5-amino-1-(5-phospho-beta-D-ribosyl)imidazole + AH2 + S-adenosyl-L-
CA   methionine = 5'-deoxyadenosine + 5-hydroxybenzimidazole + A + formate +
CA   2 H(+) + L-methionine + NH4(+) + phosphate.
CC   -!- The enzyme, purified from bacteria, is part of the anaerobic pathway
CC       for cobalamin biosynthesis.
CC   -!- It binds a [4Fe-4S] cluster that is coordinated by 3 cysteines and an
CC       exchangeable S-adenosyl-L-methionine molecule.
CC   -!- The first stage of catalysis is reduction of the S-adenosyl-L-
CC       methionine to produce L-methionine and a 5'-deoxyadenosin-5'-yl
CC       radical that is crucial for the conversion of the substrate.
DR   A0A0K1TPY7, BZAA_EUBLI ;  Q2RHR4, BZAA_MOOTA ;  A0A0K1TQ05, BZAB_EUBLI ;
DR   Q2RHR5, BZAB_MOOTA ;  Q1JZW3, BZAF_DESA6 ;  C0QJ00, BZAF_DESAH ;
DR   Q39YG0, BZAF_GEOMG ;  P61425, BZAF_GEOSL ;
//