ID 2.1.1.272 DE cobalt-factor III methyltransferase. CA AH2 + Co(II)-factor III + S-adenosyl-L-methionine = A + Co-precorrin-4 + CA S-adenosyl-L-homocysteine. CC -!- Isolated from the bacterium Bacillus megaterium. CC -!- The enzyme, which participates in the anaerobic (early cobalt CC insertion) pathway of adenosylcobalamin biosynthesis, catalyzes a CC crucial reaction where the tetrapyrrole ring contracts as a result of CC methylation of C-17. CC -!- Contains a [4Fe-4S] cluster. CC -!- It can also convert cobalt-precorrin-3 to cobalt-precorrin-4. CC -!- The reductant may be thioredoxin. CC -!- See EC 2.1.1.131 for the corresponding enzyme that participates in CC the aerobic cobalamin biosynthesis pathway. DR O87689, CBIH_PRIMG ; //