Ye Qing, Ji Quan-Quan, Yan Wei, Yang Fang, Wang En-Duo
From the State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Science, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China and.
From the State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Science, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China and
J Biol Chem. 2017 Jun 23;292(25):10709-10722. doi: 10.1074/jbc.M116.770826. Epub 2017 Apr 28.
Previous proteomic analyses have shown that aminoacyl-tRNA synthetases in many organisms can be modified by acetylation of Lys. In this present study, leucyl-tRNA synthetase and arginyl-tRNA synthetase from (LeuRS and ArgRS) were overexpressed and purified and found to be acetylated on Lys residues by MS. Gln scanning mutagenesis revealed that Lys, Lys, and Lys in LeuRS and Lys and Lys in ArgRS might play important roles in enzyme activity. Furthermore, we utilized a novel protein expression system to obtain enzymes harboring acetylated Lys at specific sites and investigated their catalytic activity. Acetylation of these Lys residues could affect their aminoacylation activity by influencing amino acid activation and/or the affinity for tRNA. assays showed that acetyl-phosphate nonenzymatically acetylates LeuRS and ArgRS and suggested that the sirtuin class deacetylase CobB might regulate acetylation of these two enzymes. These findings imply a potential regulatory role for Lys acetylation in controlling the activity of aminoacyl-tRNA synthetases and thus protein synthesis.
先前的蛋白质组学分析表明，许多生物体中的氨酰-tRNA合成酶可被赖氨酸乙酰化修饰。在本研究中，来自[具体来源未提及]的亮氨酰-tRNA合成酶和精氨酰-tRNA合成酶（LeuRS和ArgRS）被过表达并纯化，通过质谱发现它们的赖氨酸残基被乙酰化。谷氨酰胺扫描诱变显示，LeuRS中的赖氨酸、赖氨酸和赖氨酸以及ArgRS中的赖氨酸和赖氨酸可能在酶活性中起重要作用。此外，我们利用一种新型蛋白质表达系统获得在特定位点含有乙酰化赖氨酸的酶，并研究了它们的催化活性。这些赖氨酸残基的乙酰化可通过影响氨基酸活化和/或对tRNA的亲和力来影响它们的氨酰化活性。实验表明，乙酰磷酸可非酶促地使LeuRS和ArgRS乙酰化，并提示沉默调节蛋白类去乙酰化酶CobB可能调节这两种酶的乙酰化。这些发现暗示赖氨酸乙酰化在控制氨酰-tRNA合成酶活性从而蛋白质合成方面具有潜在的调节作用。
