Chen Bingyi, Yi Fang, Luo Zhiteng, Lu Feihu, Liu Hongwei, Luo Siting, Gu Qiong, Zhou Huihao
State Key Laboratory of Anti-Infective Drug Discovery and Development, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China.
Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China.
Nat Commun. 2024 Dec 30;15(1):10817. doi: 10.1038/s41467-024-55183-0.
The faithful charging of amino acids to cognate tRNAs by aminoacyl-tRNA synthetases (AARSs) determines the fidelity of protein translation. Isoleucyl-tRNA synthetase (IleRS) distinguishes tRNA from tRNA solely based on the nucleotide at wobble position (N34), and a single substitution at N34 could exchange the aminoacylation specificity between two tRNAs. Here, we report the structural and biochemical mechanism of N34 recognition-based tRNA discrimination by Saccharomyces cerevisiae IleRS (ScIleRS). ScIleRS utilizes a eukaryotic/archaeal-specific arginine as the H-bond donor to recognize the common carbonyl group (H-bond acceptor) of various N34s of tRNA, which induces mutual structural adaptations between ScIleRS and tRNA to achieve a preferable editing state. C34 of unmodified tRNA(CAU) (behaves like tRNA) lacks a relevant H-bond acceptor, which disrupts key H-bonding interactions and structural adaptations and suspends the ScIleRS·tRNA(CAU) complex in an initial non-reactive state. This wobble nucleotide recognition-based structural adaptation provides mechanistic insights into selective tRNA aminoacylation by AARSs.
氨酰 - tRNA合成酶（AARSs）将氨基酸准确地加载到对应的tRNA上，这决定了蛋白质翻译的保真度。异亮氨酰 - tRNA合成酶（IleRS）仅根据摆动位置（N34）的核苷酸来区分不同的tRNA，N34处的单个取代可使两种tRNA之间的氨酰化特异性发生交换。在此，我们报道了酿酒酵母IleRS（ScIleRS）基于N34识别进行tRNA识别的结构和生化机制。ScIleRS利用真核生物/古细菌特有的精氨酸作为氢键供体，识别tRNA各种N34的共同羰基（氢键受体），这诱导了ScIleRS和tRNA之间的相互结构适应，以达到更优的编辑状态。未修饰的tRNA(CAU)（表现得像tRNA）的C34缺乏相关的氢键受体，这破坏了关键的氢键相互作用和结构适应，使ScIleRS·tRNA(CAU)复合物处于初始的非反应状态。这种基于摆动核苷酸识别的结构适应为AARSs选择性tRNA氨酰化提供了机制上的见解。
