Crystal Structures of Streptomyces Coelicolor Methylmalonyl-CoA Epimerase with Substrate or Transition State Analog Contradicts a Simple General Acid-Base Catalytic Mechanism

Crystal structures of Streptomyces coelicolor methylmalonyl-CoA epimerase in the holo-form, with substrate or the putative transition state analog, 2-nitroproionyl-CoA. The proposed catalytic mechanism is general acid-base catalysis. The proposed catalytic residues are too far from the substrate or analog, unless conformational changes take place or some other mechanism is used.