Crystallization and preliminary X-ray analysis of a family 51 glycoside hydrolase, the α-L-arabinofuranosidase from Geobacillus stearothermophilus T-6

α-L-Arabinofuranosidases (EC 3.2.1.55) are hemicellulases that cleave the glycosidic bond between L-arabinofuranoside side chains and various oligosaccharides. In this study, the first crystallization and preliminary X-ray analysis of the α-L-arabinofuranosidase from Geobacillus stearothermophilus T-6 (AbfA T-6), a family 51 glycoside hydrolase, is described. AbfA T-6 is a hexameric protein consisting of six identical subunits of 502 amino acids and with a calculated molecular mass of 57 218 Da. Purified recombinant native and selenomethionine-containing AbfA T-6 were crystallized by the sitting-drop method in two different space groups, P2₁ (unit-cell parameters a = 100.8, b = 178.1, c = 196.2 Å, β = 96.1°) and R3 (unit-cell parameters a = b = 179.3, c = 100.4 Å). The R3 crystals diffracted X-rays to a resolution of 1.8 Å.