Expression, purification, crystallization and preliminary X-ray diffraction analysis of Thermotoga neapolitana β-glucosidase B

beta-Glucosidases belong to families 1, 3 and 9 of the glycoside hydrolases and act on cello-oligosaccharides. Family 1 and 3 enzymes are retaining and are reported to have transglycosylation activity, which can be used to produce oligosaccharides and glycoconjugates. Family 3 enzymes are less well characterized than their family 1 homologues and to date only two crystal structures have been solved. Here, the expression, purification, crystallization and X-ray diffraction data of a family 3 beta-glucosidase from the hyperthermophilic bacterium Thermotoga neapolitana are reported. Crystals of selenomethionine-substituted protein have also been grown. The crystals belong to space group C222(1), with unit-cell parameters a = 74.9, b = 127.0, c = 175.2 angstrom. Native data have been collected to 2.4 angstrom resolution and the structure has been solved to 2.7 angstrom using the selenomethionine MAD method. Model building and refinement of the structure are under way.