脊椎动物ThrRS对tRNA(Thr)错误丙氨酰化的校正作用及其分子机理研究

tRNA氨酰化是蛋白质合成的核心步骤，其错误会影响细胞稳态而致病，因此需要特定的校正机制对其进行质量控制。最新研究发现脊椎动物tRNA(Thr)会被错误地丙氨酰化生成Ala-tRNA(Thr)，然而这种氨酰化错误的校正机制尚不明确。本项目将探索苏氨酰-tRNA合成酶（ThrRS）对Ala-tRNA(Thr)的校正作用，研究ThrRS与相关因子在校正过程中的关系，明确Ala-tRNA(Thr)的校正机制。同时借助X射线晶体衍射手段解析人源ThrRS与丙氨酰-3-氨基腺苷酸复合物的立体结构，分析二者在校正位点的空间构象以及相互作用，结合生化实验证据，阐明ThrRS识别和水解Ala-tRNA(Thr)的分子机理。本项目的开展有助于深入理解高等生物蛋白质合成的质量控制机制，对研究与tRNA氨酰化相关的疾病具有理论意义。同时人源ThrRS结构的解析能为以其作为药物靶点的研究提供依据。

tRNA aminoacylation is the one of crucial steps during protein synthesis, where the errors will impair the cellular proteostasis thus cause diseases. Therefore, the fidelity of tRNA aminoacylation must be strictly controlled by specific editing mechanisms. Resent research discovered that vertebrate tRNA(Thr) can be misacylated with alanine to generate Ala-tRNA(Thr). However, the editing mechanism of Ala-tRNA(Thr) is still unclear. In this project, we will explore the editing function of ThrRS to hydrolyze Ala-tRNA(Thr). Besides, the relations between ThrRS and other factors during tRNA(Thr) misacylation-editing process will be investigated to get a deep understanding on the editing mechanism. Meanwhile, by the means of X ray diffraction of crystals, we will solve the structure of human ThrRS in complex with alanyl-3-aminoadenosine, and put forward the interaction and recognition between them. Combined with the biochemical evidences, the molecular mechanism on editing of Ala-tRNA(Thr) by ThrRS will be proposed. In our project, the systematic study on the mechanism of ThrRS mediated editing of Ala-tRNA(Thr) could enhance the knowledge on prevention of errors during protein synthesis in higher organisms, which could be theoretically important for the better understanding on tRNA aminoacylation-related medical problems. In addition, the structure analysis of human ThrRS would provide insights for the research on drug development targeting ThrRS.