Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technical University of Munich, Garching, 85748, Germany.
Center for Experimental Medicine, Institute of Biochemistry and Signal Transduction, Universitätsklinikum Hamburg-Eppendorf (UKE), Hamburg, 20246, Germany.
Nat Commun. 2021 Jan 19;12(1):460. doi: 10.1038/s41467-020-20702-2.
Legionella pneumophila infects eukaryotic cells by forming a replicative organelle - the Legionella containing vacuole. During this process, the bacterial protein DrrA/SidM is secreted and manipulates the activity and post-translational modification (PTM) states of the vesicular trafficking regulator Rab1. As a result, Rab1 is modified with an adenosine monophosphate (AMP), and this process is referred to as AMPylation. Here, we use a chemical approach to stabilise low-affinity Rab:DrrA complexes in a site-specific manner to gain insight into the molecular basis of the interaction between the Rab protein and the AMPylation domain of DrrA. The crystal structure of the Rab:DrrA complex reveals a previously unknown non-conventional Rab-binding site (NC-RBS). Biochemical characterisation demonstrates allosteric stimulation of the AMPylation activity of DrrA via Rab binding to the NC-RBS. We speculate that allosteric control of DrrA could in principle prevent random and potentially cytotoxic AMPylation in the host, thereby perhaps ensuring efficient infection by Legionella.
嗜肺军团菌通过形成一个复制细胞器 - 军团菌包含的空泡来感染真核细胞。在这个过程中，细菌蛋白 DrrA/SidM 被分泌出来，并操纵囊泡运输调节剂 Rab1 的活性和翻译后修饰 (PTM) 状态。结果，Rab1 被修饰为一个单磷酸腺苷 (AMP)，这个过程被称为 AMP 化。在这里，我们使用化学方法以特定方式稳定低亲和力 Rab:DrrA 复合物，以深入了解 Rab 蛋白与 DrrA 的 AMP 化结构域之间的相互作用的分子基础。Rab:DrrA 复合物的晶体结构揭示了一个以前未知的非传统 Rab 结合位点 (NC-RBS)。生化特性表明，通过 Rab 与 NC-RBS 的结合，对 DrrA 的 AMP 化活性进行变构刺激。我们推测，DrrA 的变构控制原则上可以防止宿主中随机且潜在细胞毒性的 AMP 化，从而确保军团菌的有效感染。
