Rodrigues Maria L, Archer Margarida, Martel Paulo, Jacquet Alain, Cravador Alfredo, Carrondo Maria A
Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, ITQB-UNL, Av. República, Apt 127, 2781-901 Oeiras, Portugal.
Acta Crystallogr D Biol Crystallogr. 2002 Aug;58(Pt 8):1314-21. doi: 10.1107/s0907444902010107. Epub 2002 Jul 20.
Phytophthora and Pythium species are among the most aggressive plant pathogens, as they invade many economically important crops and forest trees. They secrete large amounts of 10 kDa proteins called elicitins that can act as elicitors of plant defence mechanisms. These proteins may also induce a hypersensitive response (HR) including plant cell necrosis, with different levels of toxicity depending on their pI. Recent studies showed that elicitins function as sterol carrier proteins. The crystallographic structure of the highly necrotic recombinant beta-cinnamomin (beta-CIN) from Phytophthora cinnamomi has been determined at 1.8 A resolution using the molecular-replacement method. beta-CIN has the same overall structure as beta-cryptogein (beta-CRY), an elicitin secreted by Phytophthora cryptogea, although it shows a different surface electrostatic potential distribution. The protein was expressed in Pichia pastoris and crystallized in the triclinic space group with two monomers in the asymmetric unit. The interface formed by these two monomers resembles that from beta-CRY dimer, although with fewer interactions.
疫霉菌和腐霉菌是最具侵略性的植物病原体之一，因为它们会侵害许多具有重要经济价值的农作物和林木。它们会分泌大量被称为激发子的10 kDa蛋白质，这些蛋白质可作为植物防御机制的激发子。这些蛋白质还可能引发超敏反应（HR），包括植物细胞坏死，其毒性水平因它们的pI而异。最近的研究表明，激发子起着固醇载体蛋白的作用。利用分子置换法，已在1.8 Å分辨率下确定了来自樟疫霉的高度坏死性重组β-肉桂霉素（β-CIN）的晶体结构。β-CIN与由隐地疫霉分泌的激发子β-隐地蛋白（β-CRY）具有相同的整体结构，尽管它显示出不同的表面静电势分布。该蛋白在毕赤酵母中表达，并在三斜晶系空间群中结晶，不对称单元中有两个单体。这两个单体形成的界面类似于β-CRY二聚体的界面，尽管相互作用较少。
