What is the identity of the metal ions in the active sites of coenzyme B12-dependent diol dehydratase? A computational mutation analysis.

What is the identity of the metal ion in the active sites of diol dehydratase? To address this question, we calculated the M-O bond lengths in the active sites using QM/MM calculations (M=K, Na, Mg, Ca). Our results show that the previous assignment of the metal ion in the substrate-binding site is wrong and that the identity of the metal ion is likely to be Ca2+. This is consistent with accumulated experimental evidence.