Ye Fengping, Liang Lianming, Mi Qili, Yang Jinkui, Lou Zhiyong, Sun Yuna, Guo Yu, Meng Zhaohui, Zhang Keqin
Yunnan University, Kunming, People's Republic of China.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2009 Mar 1;65(Pt 3):271-4. doi: 10.1107/S1744309109003595. Epub 2009 Feb 26.
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 A, respectively. These analyses identified that crystals of Ver112 belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 43.7, b = 67.8, c = 76.3 A, alpha = beta = gamma = 90 degrees . In contrast, crystals of the PL646-MSU-AAPV complex belonged to space group P2(1), with unit-cell parameters a = 65.1, b = 62.5, c = 67.6 A, beta = 92.8 degrees .
角质层降解蛋白酶是一类胞外枯草杆菌蛋白酶样丝氨酸蛋白酶，由昆虫病原真菌和食线虫真菌分泌。这些蛋白酶在侵染昆虫或线虫过程中能够消化宿主的角质层，并且在食线虫真菌感染线虫期间作为一组重要的毒力因子。为了阐明这些蛋白酶与线虫角质层之间的相互作用机制，研究了两种角质层降解蛋白酶，即来自淡紫拟青霉（曾用名：淡紫丝核菌）的Ver112和来自淡紫拟青霉的PL646。采用悬滴气相扩散法在289 K下使Ver112蛋白以及PL646与底物样四肽抑制剂甲氧基琥珀酰 - 丙氨酸 - 丙氨酸 - 脯氨酸 - 缬氨酸 - 氯甲基酮（MSU - AAPV）的复合物结晶。通过X射线衍射分别对晶体进行分析，分辨率分别为1.65 Å和2.2 Å。这些分析确定Ver112晶体属于空间群P2(1)2(1)2(1)，晶胞参数为a = 43.7、b = 67.8、c = 76.3 Å，α = β = γ = 90°。相比之下，PL646 - MSU - AAPV复合物的晶体属于空间群P2(1)，晶胞参数为a = 65.1、b = 62.5、c = 67.6 Å，β = 92.8°。
