细菌对现有抗生素的耐药性日趋严重，亟需研发新机制和新骨架的抗菌药物。氨酰tRNA合成酶（AARS）是蛋白质合成通路的一组关键酶，被证实是抗耐药菌的有效靶标。前期研究中，我们发现脯氨酰tRNA合成酶（ProRS）的抑制剂常山酮具有新颖的“ATP辅助的tRNA-氨基酸双位点抑制”机制，揭示tRNA结合位点是新的可药位点。基于AARS家族成员间的相似性，本项目拟将常山酮的羟基哌啶环（模拟脯氨酸）替换为其它氨基酸或模拟结构，设计、合成其它AARS成员的tRNA-氨基酸双位点抑制剂；在此基础上，共价连接新抑制剂与ATP类似物，进而合成全新的tRNA-氨基酸-ATP三位点抑制剂；利用靶标-抑制剂共晶结构指导抑制剂的结构优化；开展抑制剂抗菌活性评价与作用机制研究。本项目的实施，将基于常山酮骨架发展出AARS家族的多种新型抑制剂，获得具有开发前景的先导化合物，为研发靶向AARS家族的抗菌新药打下基础。

Antibiotic resistance is growing very fast, and new antibacterial drugs with novel mechanisms and scaffolds are urgently needed. Aminoacyl-tRNA synthetases (AARS) are a group of essential enzymes for protein synthesis, and they are a class of validated antibacterial drug targets. In previous studies, we found that the halofuginone inhibits prolyl-tRNA synthetase (ProRS) through a novel "ATP-dependent tRNA-amino acid dual-site inhibition" mechanism, revealing that the binding pocket of the tRNA 3'-end is a new druggable site. Based on the similarity across AARS family, herein we plan to substitute the hydroxypiperidine ring (mimic of substrate proline) of halofuginone with other L-amino acids or amino acid analogs, to design and synthesize new tRNA-amino acid dual-site inhibitors for other AARS family members. After that, we will covalently link the new synthesized inhibitors with ATP analogs to generate novel tRNA-amino acid-ATP triple-site inhibitors. These new inhibitors will be further optimized under the guidance of target-inhibitor cocrystal structures, and their antibacterial activity and mechanisms will also be studied. This project will create a class of new AARS inhibitors based on the molecular scaffold of halofuginone, and produce one or more promising lead compounds, which will pave a road for developing AARS-targeted new antibacterial drugs.