I. Serine proteinases. The structure of α-chymotrypsin

Abstract

A newly calculated electron density map has allowed a more detailed description of the molecular structure to be given. The structure can be described in detail in relation to the probable existence of hydrogen bonds and the conformations of side chains. The discovery of a new buried acid group which is part of a hydrogen bonding system involving the active serine has indicated how this serine can become a powerful nucleophile, by means of a ‘charge relay system'. Diffraction studies of the binding of various substituents, coupled with accurate model building, have defined the catalytic binding site.