X-ray crystallographic analysis of the catalytic domain of α-1,3-glucanase FH1 from Paenibacillus glycanilyticus overexpressed in Brevibacillus choshinensis.

α-1,3-Glucanase hydrolyzes α-1,3-glucan, an insoluble linear α-1,3-linked homopolymer of glucose that is found in the extracellular polysaccharides produced by oral streptococci in dental plaque and in fungal cell walls. This enzyme could be of application in dental care and the development of fungal cell-wall lytic enzymes, but its three-dimensional structure has not been available to date. In this study, the recombinant catalytic domain of α-1,3-glucanase FH1 from Paenibacillus glycanilyticus FH11, which is classified into glycoside hydrolase family 87, was prepared using a Brevibacillus choshinensis expression system and purified in a soluble form. Crystals of the purified protein were produced by the sitting-drop vapor-diffusion method. Diffraction data were collected to a resolution of 1.6 Å using synchrotron radiation. The crystals obtained belonged to the tetragonal space group P41212 or P43212, with unit-cell parameters a = b = 132.6, c = 76.1 Å. The space group and unit-cell parameters suggest that there is one molecule in the asymmetric unit.