Crystallization and preliminary X-ray analysis of the catalytic domains of Paenibacillus sp. strain FPU-7 cell-surface-expressed chitinase ChiW

The polysaccharide chitin is effectively hydrolyzed and utilized as a carbon and nitrogen source by the Gram-positive bacterium Paenibacillus sp. strain FPU-7. ChiW is a unique cell-surface-expressed chitinase among the Paenibacillus sp. strain FPU-7-secreted chitinases. An N-terminally truncated ChiW protein, primarily comprised of the two catalytic domains of the full-length protein, was successfully overexpressed in Escherichia coli, purified as a functional recombinant protein with a molecular mass of approximately 98 kDa and crystallized. Preliminary X-ray analysis showed that the crystal diffracted to 1.93 Å resolution and belonged to the orthorhombic space group P2₁2₁2₁, with unit-cell parameters a = 112.1, b = 128.2, c = 162.6 Å, suggesting the presence of two molecules in an asymmetric unit.