||In the aerobic cobalamin biosythesis pathway, four enzymes are involved in the conversion of precorrin-3A to precorrin-6A. The first of the four steps is carried out by EC 18.104.22.168, precorrin-3B synthase (CobG), yielding precorrin-3B as the product. This is followed by three methylation reactions, which introduce a methyl group at C-17 (CobJ; EC 22.214.171.124), C-11 (CobM; EC 126.96.36.199) and C-1 (CobF; EC 188.8.131.52) of the macrocycle, giving rise to precorrin-4, precorrin-5 and precorrin-6A, respectively.
||Crouzet, J., Cameron, B., Cauchois, L., Rigault, S., Rouyez, M.C., Blanche, F. , Thibaut D., Debussche, L. Genetic and sequence analysis of an 8.7-kilobase Pseudomonas denitrificans fragment carrying eight genes involved in transformation of precorrin-2 to cobyrinic acid. J. Bacteriol. 172 (1990) 5980–5990. [PMID: 2211521]
||Roth, J.R., Lawrence, J.G., Rubenfield, M., Kieffer-Higgins, S., Church, G.M. Characterization of the cobalamin (vitamin B12) biosynthetic genes of Salmonella typhimurium. J. Bacteriol. 175 (1993) 3303–3316. [PMID: 8501034]