Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China.
Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, 310014, Zhejiang, China.
Sci Rep. 2018 Feb 5;8(1):2435. doi: 10.1038/s41598-018-20802-6.
Enhanced intracellular survival (Eis) proteins were found to enhance the intracellular survival of mycobacteria in macrophages by acetylating aminoglycoside antibiotics to confer resistance to these antibiotics and by acetylating DUSP16/MPK-7 to suppress host innate immune defenses. Eis homologs composing of two GCN5 N-acetyltransferase regions and a sterol carrier protein fold are found widely in gram-positive bacteria. In this study, we found that Eis proteins have an unprecedented ability to acetylate many arylalkylamines, are a novel type of arylalkylamine N-acetyltransferase AANAT (EC 2.3.1.87). Sequence alignment and phyletic distribution analysis confirmed Eis belongs to a new aaNAT-like cluster. Among the cluster, we studied three typical Eis proteins: Eis_Mtb from Mycobacterium tuberculosis, Eis_Msm from Mycobacterium smegmatis, and Eis_Sen from Saccharopolyspora erythraea. Eis_Mtb prefers to acetylate histamine and octopamine, while Eis_Msm uses tyramine and octopamine as substrates. Unlike them, Eis_Sen exihibits good catalytic efficiencies for most tested arylalkylamines. Considering arylalkylamines such as histamine plays a fundamental role in immune reactions, future work linking of AANAT activity of Eis proteins to their physiological function will broaden our understanding of gram-positive pathogen-host interactions. These findings shed insights into the molecular mechanism of Eis, and reveal potential clinical implications for many gram-positive pathogens.
发现增强型细胞内生存（Eis）蛋白通过将氨基糖苷类抗生素乙酰化来赋予其对这些抗生素的抗性，并通过乙酰化 DUSP16/MPK-7 来抑制宿主固有免疫防御，从而增强分枝杆菌在巨噬细胞中的细胞内生存。由两个 GCN5 N-乙酰转移酶区域和固醇载体蛋白折叠组成的 Eis 同源物广泛存在于革兰氏阳性菌中。在这项研究中，我们发现 Eis 蛋白具有前所未有的乙酰化许多芳基烷基胺的能力，是一种新型的芳基烷基胺 N-乙酰转移酶 AANAT（EC 2.3.1.87）。序列比对和系统发育分布分析证实 Eis 属于一个新的 aaNAT 样簇。在该簇中，我们研究了三种典型的 Eis 蛋白：来自结核分枝杆菌的 Eis_Mtb、来自耻垢分枝杆菌的 Eis_Msm 和来自红色糖多孢菌的 Eis_Sen。Eis_Mtb 优先乙酰化组氨酸和章鱼胺，而 Eis_Msm 则使用酪胺和章鱼胺作为底物。与它们不同的是，Eis_Sen 对大多数测试的芳基烷基胺表现出良好的催化效率。考虑到诸如组氨酸的芳基烷基胺在免疫反应中起着根本作用，未来将 Eis 蛋白的 AANAT 活性与其生理功能联系起来的工作将拓宽我们对革兰氏阳性病原体-宿主相互作用的理解。这些发现深入了解了 Eis 的分子机制，并揭示了许多革兰氏阳性病原体的潜在临床意义。
