H NMR results demonstrated that the Y168L-A361P mutation enhances the carboxylation rate to a much greater extent than does the oxygenation rate. Molecular-dynamics simulations revealed that Y168L and A361P─although neither contacts the substrate directly─augment binding of the carboxylation intermediate EI II through an extended interaction network that strengthens hydrogen bonds to the substrate carboxylate.
Li et al. (Mon,) studied this question.