Proposed mechanism for the condensation reaction of citrate synthase: 1.9-A structure of the ternary complex with oxaloacetate and carboxymethyl coenzyme A.

摘要: The crystal structure of the ternary complex citrate synthase-oxaloacetate-carboxymethyl coenzyme A has been solved to a resolution 1.9 and refined conventional crystallographic R factor 0.185. resembles proposed transition state condensation reaction suggests that proceeds through neutral enol rather than an enolate intermediate. mechanism for is which involves participation three key catalytic groups (Asp 375, His 274, 320) in two distinct steps. invokes concerted general acid-base catalysis twice explain both energetics experimentally observed inversion stereochemistry at attacking carbon atom.