Abstract
WAS-3 protein, a member of PR-5 family, accumulates in an apoplastic space of winter wheat in response to cold acclimation. We previously revealed that recombinant WAS-3 protein (rWAS-3) produced using high efficiency wheat expression system inhibited hyphal growth of pink snow mold and Fusarium oxysporum. Furthermore, rWAS-3 bound to fungal cell wall itself and β-1,3-glucan that was main components of fungal cell walls. In order to clarify the biochemical interaction of WAS-3 and β-1,3-glucan, we determined the crystal structure of rWAS-3 using X-ray crystallographic analysis. The thin plate-shaped crystals of rWAS-3 were obtained by hanging-drop vapor diffusion method. The structure of rWAS-3 was determined at 1.8 angstrom resolution by molecular replacement method. The electrostatic potential analysis revealed that rWAS-3 had an acidic cleft region. Therefore, we concluded that this region might be β-1,3-glucan binding site of rWAS-3.
