The near attack conformation approach to the study of the chorismate to prephenate reaction

Standard free energies (DeltaG(N)degrees) for formation of near attack conformers, those ground state conformers that can convert directly to the transition state, were calculated for the Claisen rearrangement of chorismate to prephenate in six different environments: water, wild-type enzymes from Bacillus subtilis and Escherichia coli, their Arg90Cit and Glu52Ala mutants, and the 1F7 catalytic antibody. Values of the calculated DeltaG(N)degreess and the experimentally determined activation energies (DeltaG(double dagger)) are linearly related with the slope of approximate to1. This demonstrates that the relative rate of the chorismate --> prephenate reaction is overwhelmingly dependent on the efficiency of formation of near attack conformers in the ground state.