High-level QM/MM modelling predicts an arginine as the acid in the condensation reaction catalysed by citrate synthase.

ABSTRACT

High-level ab initio quantum mechanical/molecular mechanical (QM/MM) modelling of citryl-CoA formation in citrate synthase reveals that an arginine residue acts as the proton donor; this proposed new mechanism helps to explain how chemical and large scale conformational changes are coupled in this paradigmatic enzyme.