Phelps Steven S, Malkiewicz Andrzej, Agris Paul F, Joseph Simpson
Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0314, USA.
J Mol Biol. 2004 Apr 30;338(3):439-44. doi: 10.1016/j.jmb.2004.02.070.
Ribosomes translate genetic information encoded by messenger RNAs (mRNAs) into proteins. Accurate decoding by the ribosome depends on the proper interaction between the mRNA codon and the anticodon of transfer RNA (tRNA). tRNAs from all kingdoms of life are enzymatically modified at distinct sites, particularly in and near the anticodon. Yet, the role of these naturally occurring tRNA modifications in translation is not fully understood. Here we show that modified nucleosides at the first, or wobble, position of the anticodon and 3'-adjacent to the anticodon are important for translocation of tRNA from the ribosome's aminoacyl site (A site) to the peptidyl site (P site). Thus, naturally occurring modifications in tRNA contribute functional groups and conformational dynamics that are critical for accurate decoding of mRNA and for translocation to the P site during protein synthesis.
核糖体将信使核糖核酸（mRNA）编码的遗传信息翻译成蛋白质。核糖体的准确解码取决于mRNA密码子与转运核糖核酸（tRNA）反密码子之间的正确相互作用。来自所有生命王国的tRNA在不同位点，特别是在反密码子内部及附近，会发生酶促修饰。然而，这些天然存在的tRNA修饰在翻译中的作用尚未完全了解。在这里，我们表明反密码子第一个或摆动位置以及反密码子3'相邻位置的修饰核苷对于tRNA从核糖体的氨酰基位点（A位点）转移到肽酰基位点（P位点）很重要。因此，tRNA中天然存在的修饰提供了功能基团和构象动力学，这对于mRNA的准确解码以及蛋白质合成过程中向P位点的转移至关重要。
