Elucidation of reaction mechanism for post-transcriptional modification at tRNA anticodon region

tRNA^ UUC、tRNA^ UUU、tRNA^UUG中tRNA反密码子（U34）第一位的尿苷<Glu><Lys><Gln>被修饰为5-羧甲基氨基甲基-2-硫代尿苷（cmnm^5s^2U），这对遗传密码的精确解码至关重要。在真细菌中，两种保守蛋白GidA和MnmE负责将cmnm 5基团添加到U34的5位。在这里，我们报告的晶体结构的GidA和MnmE。结合突变研究，我们提出了cmnm^5U修饰过程的新机制。

The uridine at the first position of the tRNA anticodon (U34) in tRNA^<Glu>UUC, tRNA^<Lys>UUU, tRNA^<Gln>UUG is modified to 5-carboxymethylaminomethyl-2-thiouridine (cmnm^5s^2U), which is crucial for the precise decoding of the genetic code. In eubacteria, two conserved proteins, GidA and MnmE, are responsible for adding the cmnm5 group to the 5-position of U34. Here we report the crystal structures of GidA and MnmE. Together with the mutational study, we propose a novel mechanism for the cmnm^5U modification process.