Delagoutte B, Moras D, Cavarelli J
UPR 9004 Biologie et Génomique Structurales, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, BP 163, 67404 Illkirch Cedex, France.
EMBO J. 2000 Nov 1;19(21):5599-610. doi: 10.1093/emboj/19.21.5599.
The 2.2 A crystal structure of a ternary complex formed by yeast arginyl-tRNA synthetase and its cognate tRNA(Arg) in the presence of the L-arginine substrate highlights new atomic features used for specific substrate recognition. This first example of an active complex formed by a class Ia aminoacyl-tRNA synthetase and its natural cognate tRNA illustrates additional strategies used for specific tRNA selection. The enzyme specifically recognizes the D-loop and the anticodon of the tRNA, and the mutually induced fit produces a conformation of the anticodon loop never seen before. Moreover, the anticodon binding triggers conformational changes in the catalytic center of the protein. The comparison with the 2.9 A structure of a binary complex formed by yeast arginyl-tRNA synthetase and tRNA(Arg) reveals that L-arginine binding controls the correct positioning of the CCA end of the tRNA(Arg). Important structural changes induced by substrate binding are observed in the enzyme. Several key residues of the active site play multiple roles in the catalytic pathway and thus highlight the structural dynamics of the aminoacylation reaction.
酵母精氨酰 - tRNA合成酶与其同源tRNA（Arg）在L - 精氨酸底物存在下形成的三元复合物的2.2 Å晶体结构突出了用于特异性底物识别的新原子特征。这是由I类氨酰 - tRNA合成酶及其天然同源tRNA形成的活性复合物的首个实例，阐明了用于特异性tRNA选择的其他策略。该酶特异性识别tRNA的D环和反密码子，相互诱导契合产生了前所未见的反密码子环构象。此外，反密码子结合引发了蛋白质催化中心的构象变化。与酵母精氨酰 - tRNA合成酶和tRNA（Arg）形成的二元复合物的2.9 Å结构相比，发现L - 精氨酸结合控制了tRNA（Arg）的CCA末端的正确定位。在酶中观察到底物结合诱导的重要结构变化。活性位点的几个关键残基在催化途径中发挥多种作用，从而突出了氨酰化反应的结构动力学。
