Purification, crystallization and preliminary X‐ray analysis of a thermostable glycoside hydrolase family 43 β‐xylosidase from Geobacillus thermoleovorans IT‐08

The main enzymes involved in xylan‐backbone hydrolysis are endo‐1,4‐β‐xylanase and β‐xylosidase. β‐Xylosidase converts the xylo‐oligosaccharides produced by endo‐1,4‐β‐xylanase into xylose monomers. The β‐xylosidase from the thermophilic Geobacillus thermoleovorans IT‐08, a member of glycoside hydrolase family 43, was crystallized at room temperature using the hanging‐drop vapour‐diffusion method. Two crystal forms were observed. Bipyramid‐shaped crystals belonging to space group P 4 3 2 1 2, with unit‐cell parameters a  =  b  = 62.53, c = 277.4 Å diffracted to 1.55 Å resolution. The rectangular crystals belonged to space group P 2 1 , with unit‐cell parameters a  = 57.94, b  = 142.1, c = 153.9 Å, β = 90.5°, and diffracted to 1.80 Å resolution.