The reactivity of B12 cofactors: the proteins make a difference

AbstractDetermination of the structure of intact methylmalonyl-CoA mutase from Propionibacterium shermanii, and comparisons with the structure of the cobalamin-binding fragment of methionine synthase from Escherichia coli, afford a first glimpse at the similarities and distinctions between the two principal classes of B12-dependent enzymes: the mutases and the methyltransferases