Preliminary crystallographic study of two cuticle‐degrading proteases from the nematophagous fungi Lecanicillium psalliotae and Paecilomyces lilacinus

Cuticle‐degrading proteases are extracellular subtilisin‐like serine proteases that are secreted by entomopathogenic and nematophagous fungi. These proteases can digest the host cuticle during invasion of an insect or nematode and serve as a group of important virulence factors during the infection of nematodes by nematophagous fungi. To elucidate the mechanism of interaction between the proteases and the nematode cuticle, two cuticle‐degrading proteases, Ver112 from Lecanicillium psalliotae (syn. Verticillium psalliotae ) and PL646 from Paecilomyces lilacinus , were studied. The Ver112 protein and the complex between PL646 and the substrate‐like tetrapeptide inhibitor methoxysuccinyl‐Ala‐Ala‐Pro‐Val‐chloromethyl ketone (MSU‐AAPV) were crystallized using the hanging‐drop vapour‐diffusion method at 289 K. The crystals were analyzed by X‐ray diffraction to resolutions of 1.65 and 2.2 Å, respectively. These analyses identified that crystals of Ver112 belonged to space group P 2 1 2 1 2 1 , with unit‐cell parameters a = 43.7, b = 67.8, c = 76.3 Å, α = β = γ = 90°. In contrast, crystals of the PL646–MSU‐AAPV complex belonged to space group P 2 1 , with unit‐cell parameters a = 65.1, b = 62.5, c = 67.6 Å, β = 92.8°.