The Chitopentaose Complex of a Mutant Hen Egg-White Lysozyme Displays No Distortion of the —1 Sugar Away from a ~4C1 Chair Conformation

摘要

Glycosidase inhibitors frequently reflect either the charge or the 'flattened' shape of the oxocarbenium-ion like transition state. Much of the impetus for such inhibitory strategies derives from historical studies on ligand binding to hen egg white lysozyme (HEWL); not least those suggesting that product complexes of the enzyme showed distortion of the pyranosides in the — 1 subsite. Ironically, while distortion is undoubtedly a defining feature of glycosidases, product complexes themselves are rarely distorted. Here we show that the chitopentaose product complex of a mutant E35Q HEWL, solved at 1.8 A resolution, is bound with all sugars in ~4C1 conformation.