Crystallization and preliminary X-ray analysis of Streptococcus mutans dextran glucosidase

Dextran glucosidase from Streptococcus mutans is an exo-hydrolase that acts on the nonreducing terminal α-1,6-glucosidic linkage of oligosaccharides and dextran with a high degree of transglucosylation. Based on amino-acid sequence similarity, this enzyme is classified into glycoside hydrolase family 13. Recombinant dextran glucosidase was purified and crystallized by the hanging-drop vapour-diffusion technique using polyethylene glycol 6000 as a precipitant. The crystals belong to the orthorhombic space group P2₁2₁2₁, with unit-cell parameters a = 72.72, b = 86.47, c = 104.30 Å. A native data set was collected to 2.2 Å resolution from a single crystal.