Crystallization and preliminary crystallographic analysis of β-mannanase from Bacillus licheniformis

The mannan endo-1,4-β-mannosidase (ManB) from Bacillus licheniformis strain DSM13 was overexpressed in Escherichia coli. Purification of the thermostable and alkali-stable recombinant mannanase yielded approximately 50 mg enzyme per litre of culture. Crystals were grown by hanging-drop vapour diffusion using a precipitant solution consisting of 12%(w/v) PEG 8000, 0.2 M magnesium acetate tetrahydrate and 0.1 M MES pH 6.5. The protein crystallized in the monoclinic space group P2₁, with two molecules per asymmetric unit and unit-cell parameters a = 48.58, b = 91.75, c = 89.55 Å, β = 98.29°, and showed diffraction to 2.3 Å resolution.