Mammalian trans-editing factor ProX is able to deacylate tRNAThr mischarged with alanine.
Mammalian trans-editing factor ProX is able to deacylate tRNAThr mischarged with alanine.
复制标题
DOI：
10.1016/j.ijbiomac.2023.127121
复制
发表时间：
2023-09
影响因子：
8.2
通讯作者：
Chen Yuan;Zihan Li;Xinyu Luo;Pingping Huang;Lijie Guo;Meiling Lu;Jie Xia;Yibei Xiao;Xiao-Long Zhou;Meirong Chen
中科院分区：
文献类型：
--
作者：
Chen Yuan;Zihan Li;Xinyu Luo;Pingping Huang;Lijie Guo;Meiling Lu;Jie Xia;Yibei Xiao;Xiao-Long Zhou;Meirong Chen
tRNA与其同源氨基酸的精确偶联，称为tRNA氨酰化，是一个严格调控的过程，控制翻译保真度。为了确保保真度，生物体部署多层编辑机制来纠正错误的tRNA。先前的研究已经揭示了真核AlaRS错误地将丙氨酸连接到以G4：U69碱基对为特征的tRNACys和tRNAThr上的倾向。鉴于此，并考虑到ProXp-ala在Ala-tRNAPro去酰化中的能力，我们开始探索thistransans编辑因子是否可以扩展其纠正功能以涵盖这些错误的tRNA。我们的体外脱酰实验表明，鼠ProXp-ala（mProXp-ala）能够有效地水解Ala-tRNAThr，而Ala-tRNACys不受影响。随后，我们确定了真核ProXp-ala的第一个结构，揭示了一个参与底物结合的动态螺旋α2。结合分子动力学模拟和生物化学分析，我们确定了mProXp-ala和Ala-tRNA之间的关键相互作用，其中mProXp-ala的碱性区域以及C3-G70在识别中起着至关重要的作用。这些观察结果共同为mProXp-ala对Ala-tRNAThr的脱酰能力提供了令人信服的理由。我们的研究结果为高等真核生物的翻译质量控制提供了有价值的见解，其中翻译的保真度受到广泛记录的蛋白质的多功能性的保障。
The precise coupling of tRNAs with their cognate amino acids, known as tRNA aminoacylation, is a stringently regulated process that governs translation fidelity. To ensure fidelity, organisms deploy multiple layers of editing mechanisms to correct mischarged tRNAs. Prior investigations have unveiled the propensity of eukaryotic AlaRS to erroneously attach alanine onto tRNACysand tRNAThrfeaturing the G4:U69 base pair. In light of this, and given ProXp-ala's capacity in deacylating Ala-tRNAPro, we embarked on exploring whether thistrans-editing factor could extend its corrective function to encompass these mischarged tRNAs. Ourin vitrodeacylation assays demonstrate that murine ProXp-ala (mProXp-ala) is able to efficiently hydrolyze Ala-tRNAThr, while Ala-tRNACysremains unaffected. Subsequently, we determined the first structure of eukaryotic ProXp-ala, revealing a dynamic helix α2 involved in substrate binding. By integrating molecular dynamics simulations and biochemical assays, we pinpointed the pivotal interactions between mProXp-ala and Ala-tRNA, wherein the basic regions of mProXp-ala as well as the C3-G70 plays essential role in recognition. These observations collectively provide a cogent rationale for mProXp-ala's deacylation proficiency against Ala-tRNAThr. Our findings offer valuable insights into the translation quality control within higher eukaryotic organisms, where the fidelity of translation is safeguarded by the multi-functionality of extensively documented proteins.