Determination of the structure of intact methylmalonyl-CoA mutase from
Propionibacterium shermanii, and comparisons with the structure of th
e cobalamin-binding fragment of methionine synthase from Escherichia c
oli, afford a first glimpse at the similarities and distinctions betwe
en the two principal classes of B-12-dependent enzymes: the mutases an
d the methyltransferases.