A hydrogen-bond network at the active site of subtilisin BPN'

Abstract

Further examination of the active site region in our X-ray crystallographic model of subtilisin BPN' reveals a hydrogen-bond network that bears a remarkable resemblance to the one found in a- chymotrypsin. It involves the side chains of the reactive Ser-221, His-64, Asp-32 and Ser-33. Otherwise the two enzymes have entirely different three-dimensional structures. This observation suggests that the common hydrogen bond network plays some essential role in the catalytic mechanism of serine proteases generally.