Crystallization and preliminary X-ray diffraction studies of a novel alkaline serine protease (KP-43) from alkaliphilic Bacillus sp. strain KSM-KP43

A novel alkaline serine protease (KP-43) which belongs to a new class of the subtilisin superfamily was crystallized by the sitting-drop vapour-diffusion method with ammonium sulfate as a precipitant. The crystals belong to the orthorhombic space group C222₁, with unit-cell parameters a = 43.50 (2), b = 110.4 (1), c = 168.9 (1) Å. The crystals diffract X-rays beyond 1.9 Å resolution using Cu Kα radiation from a rotating-anode generator and are suitable for high-resolution crystal structure analysis.