Crystal structure of a complex between thermitase from Thermoactinomyces vulgaris and the leech inhibitor eglin

Abstract

Thermitase, the thermostable alkaline protease from Thermoactinomyces vulgaris, has been crystallised in a 1:1 complex with eglin, the inhibitor from the medical leech. Two large crystals were grown, with cell dimensions of a = 49.3 Å, b = 67.3 Å, c = 90.5 Å and space group P212121. The crystals are relatively tightly packed with Vm = 2.1 Å3/Da. Three-dimensional data to 1.9 Å have been recorded from one of these crystals. The orientation and position of the complex in the unit cell have been established using the subtilisin Carlsberg-eglin structure as a model. The structure of the complex is being refined by restrained least-squares. The present crystallographic R factor (= Σ|Fo-Fc|/Σ|Fo) is 26% at 2.5 Å resolution. © 1988.