posted on 2022-02-05, 05:03authored byYujia Wang, Michel Rickhaus, Olivier Blacque, Kim K. Baldridge, Michal Juríček, Jay S. Siegel
A simple abiological
host–guest system demonstrates racemase
activity with catalytic rate enhancements of 104 without
employing traditional functional groups. Cooperative weak interactions
enhanced through shape-complementarity between the catalyst active
site and the reaction transition state drive this activity, as proposed
by Pauling for enzymes. In analogy to the Jencks’ concept of
catalytic antibodies, it is shown that a hapten resembling the planar
transition state of the bowl inversion acts as a potent inhibitor
of this catalytic process. In contrast, no substrate/product inhibition
is detected, and a relatively weak binding of the substrate is observed
(Ka ≈ 102 M–1 at 293 K). This simple box-and-bowl system demonstrates that shape
selectivity arising from cooperative dispersive forces suffices for
the emergence of a catalytic system with an enzyme-like thermodynamic
profile.