Plant Biology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA, 92037, USA.
Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA, 92037, USA.
Nat Commun. 2017 Dec 19;8(1):2201. doi: 10.1038/s41467-017-02347-w.
Several Pseudomonas and Xanthomonas species are plant pathogens that infect the model organism Arabidopsis thaliana and important crops such as Brassica. Resistant plants contain the infection by rapid cell death of the infected area through the hypersensitive response (HR). A family of highly related α/β hydrolases is involved in diverse processes in all domains of life. Functional details of their catalytic machinery, however, remained unclear. We report the crystal structures of α/β hydrolases representing two different clades of the family, including the protein SOBER1, which suppresses AvrBsT-incited HR in Arabidopsis. Our results reveal a unique hydrophobic anchor mechanism that defines a previously unknown family of protein deacetylases. Furthermore, this study identifies a lid-loop as general feature for substrate turnover in acyl-protein thioesterases and the described family of deacetylases. Furthermore, we found that SOBER1's biological function is not restricted to Arabidopsis thaliana and not limited to suppress HR induced by AvrBsT.
几种假单胞菌和黄单胞菌是感染模式生物拟南芥和重要作物如芸苔属的植物病原体。抗性植物通过感染区域的快速细胞死亡来抵抗感染，这一过程称为过敏反应（HR）。一类高度相关的α/β 水解酶参与生命所有领域的多种过程。然而，它们的催化机制的功能细节仍然不清楚。我们报告了代表家族中两个不同分支的 α/β 水解酶的晶体结构，包括抑制拟南芥中 AvrBsT 诱导的 HR 的 SOBER1 蛋白。我们的结果揭示了一种独特的疏水性锚定机制，定义了一个以前未知的蛋白质去乙酰化酶家族。此外，这项研究还确定了一个盖子环作为酰基-蛋白硫酯酶和所描述的去乙酰化酶家族中底物周转的一般特征。此外，我们发现 SOBER1 的生物学功能不仅限于拟南芥，也不仅限于抑制由 AvrBsT 诱导的 HR。
