Preliminary X-ray diffraction analysis of thermostable β-1,4-mannanase from Aspergillus niger BK01.

β-1,4-Mannanase (β-mannanase) is a key enzyme in decomposing mannans, which are abundant components of hemicelluloses in the plant cell wall. Therefore, mannan hydrolysis is highly valuable in a wide array of industrial applications. β-Mannanase isolated from Aspergillus niger BK01 (ManBK) was classified into glycoside hydrolase family GH5. ManBK holds great potential in biotechnological applications owing to its high thermostability. Here, ManBK was expressed and purified in Pichia pastoris and the recombinant protein was crystallized. Crystals belonging to the orthorhombic space group C222₁, with unit-cell parameters a=93.58, b=97.05, c=147.84 Å, were obtained by the sitting-drop vapour-diffusion method and diffracted to 1.57 Å resolution. Structure determination using molecular-replacement methods is in progress.