Schulman L H, Pelka H
Department of Developmental Biology and Cancer, Albert Einstein College of Medicine, Bronx, NY 10461.
Science. 1989 Dec 22;246(4937):1595-7. doi: 10.1126/science.2688091.
The contribution of the anticodon to the discrimination between cognate and noncognate tRNAs by Escherichia coli Arg-tRNA synthetase has been investigated by in vitro synthesis and aminoacylation of elongator methionine tRNA (tRNA(mMet) mutants. Substitution of the Arg anticodon CCG for the Met anticodon CAU leads to a dramatic increase in Arg acceptance by tRNA(mMet). A nucleotide (A20) previously identified by others in the dihydrouridine loop of tRNA(Arg)s makes a smaller contribution to the conversion of tRNA(mMet) identity from Met to Arg. The combined anticodon and dihydrouridine loop mutations yield a tRNA(mMet) derivative that is aminoacylated with near-normal kinetics by the Arg-tRNA synthetase.
通过体外合成和延伸因子甲硫氨酸tRNA（tRNA（mMet）突变体）的氨酰化作用，研究了大肠杆菌精氨酸tRNA合成酶的反密码子在区分同源和非同源tRNA中的作用。将精氨酸反密码子CCG替换为甲硫氨酸反密码子CAU，导致tRNA（mMet）对精氨酸的接受能力显著增加。先前其他人在tRNA（Arg）的二氢尿嘧啶环中鉴定出的一个核苷酸（A20），对tRNA（mMet）的身份从甲硫氨酸转变为精氨酸的贡献较小。反密码子和二氢尿嘧啶环的联合突变产生了一种tRNA（mMet）衍生物，它能被精氨酸tRNA合成酶以接近正常的动力学进行氨酰化。
