Crystallization and preliminary X-ray crystallographic analysis of chitosanase from Bacillus circulans MH-K1

Chitosanase, an enzyme which hydrolyzes chitosan, isolated from Bacillus circulans MH-K1, was crystallized by a vapor-diffusion procedure at 293 K using ammonium sulfate as a precipitant. Rod-shaped colorless crystals, which grew to 0.05 × 0.15 × 1.2 mm within a week, belong to the orthorhombic system and the space group P222₁ or P2₁2₁2 with unit-cell dimensions of a = 43.3, b = 57.7, and c = 128.0 Å. The asymmetric unit is thought to contain one chitosanase molecule (29 024 Da). The crystals diffract X-rays to at least 2.3 Å resolution and are suitable for high-resolution X-ray structure analysis.