泛素样修饰剂(UbL)对蛋白质的翻译后修饰,如SUMO,泛素,和Nedd8,调节大量的细胞过程。专用的UbL去偶联蛋白酶家族逆转这些修饰。在细菌感染期间,效应蛋白,包括去偶联蛋白酶,被释放以破坏宿主细胞防御并促进细菌存活。NOPD,一种来自根瘤菌的效应蛋白,参与豆科结节共生,表现出脱SUMO化活性,出乎意料的是,去泛素化和去Neddylation活性。这里,我们介绍了缓生根瘤菌的两种晶体结构(sp。XS1150)NopD与拟南芥SUMO2或泛素复合,分辨率为1.50和1.94,分别。尽管它们的序列相似性很低,SUMO和泛素结合到类似的NopD界面,在NopD序列中采用独特的环插入。体外结合和活性测定揭示了区分去泛素化和去SUMO化的特定残基。这些针对SUMO的独特多方面的解调整活动,泛素,和Nedd8举例说明了在宿主细胞感染期间破坏不同的UbL翻译后修饰的优化的细菌蛋白酶。
The post-translational modification of proteins by ubiquitin-like modifiers (UbLs), such as SUMO, ubiquitin, and Nedd8, regulates a vast array of cellular processes. Dedicated UbL deconjugating proteases families reverse these modifications. During bacterial infection, effector proteins, including deconjugating proteases, are released to disrupt host cell defenses and promote bacterial survival. NopD, an effector protein from rhizobia involved in legume nodule symbiosis, exhibits deSUMOylation activity and, unexpectedly, also deubiquitination and deNeddylation activities. Here, we present two crystal structures of Bradyrhizobium (sp. XS1150) NopD complexed with either Arabidopsis SUMO2 or ubiquitin at 1.50 Å and 1.94 Å resolution, respectively. Despite their low sequence similarity, SUMO and ubiquitin bind to a similar NopD interface, employing a unique loop insertion in the NopD sequence. In vitro binding and activity assays reveal specific residues that distinguish between deubiquitination and deSUMOylation. These unique multifaceted deconjugating activities against SUMO, ubiquitin, and Nedd8 exemplify an optimized bacterial protease that disrupts distinct UbL post-translational modifications during host cell infection.