Bedouelle H
Unité de Biochimie Cellulaire (CNRS URA D1129), Institut Pasteur, Paris, France.
Biochimie. 1990 Aug;72(8):589-98. doi: 10.1016/0300-9084(90)90122-w.
In this review, I have brought together and compared the available data on the interaction between tRNA(Tyr) and tyrosyl-tRNA synthetases (TyrTS) of prokaryotic origins. The amino acid sequences of the heterologous TyrTS that can charge Escherichia coli tRNA(Tyr), show that the residues involved in the binding and recognition of tyrosine are strictly conserved whereas those involved in the interaction with tRNA(Tyr) are only weakly similar. The results of in vivo genetic complementation experiments indicate that the identity elements of tRNAs and the recognition mechanisms of such elements by the synthetases have been conserved during evolution. Heterologous or mutant tRNA(Tyr) are quantitatively charged by E coli TyrTS; the set of their common residues contains less than 10 elements if one excludes the invariant and semi-invariant residues of tRNAs. The residues of this set are candidates for a specific recognition by TyrTS. So far, adenosine-73 is the only residue for which a specific recognition of the base has been demonstrated. The residues that might serve as identity elements for E coli tRNA(Tyr) [McClain WH, Nicholas Jr HB (1987) J Mol Biol 194, 635-642] do not belong to the above set of conserved residues and therefore probably play negative roles, enabling tRNA(Tyr) to avoid non-cognate synthetases. Comparison of the charging and stability properties of mutant tRNA(Tyr) su +3 shows that bases 1 and 72 must pair (either by Watson-Crick or non-canonical hydrogen bonds) and adopt a geometry which is compatible with the helical structure of the acceptor stem in order for the mutant tRNA(Tyr) to be charged with tyrosine. If bases 1 and 72 or bases 2 and 71 cannot form such pairings, the suppressor phenotype of the mutant tRNA(Tyr)su +3 becomes thermosensitive. The weakening of base pair 1/72 by mutation or the change of adenosine-73 into guanosine results in the charging of tRNA(Tyr)su +3 with glutamine. Comparison of the structural model of the TyrTS/tRNA(Tyr) complex with the crystallographic structure of the GlnTS/tRNA(Gln) complex indicates that the mechanisms for the recognition of the acceptor arm are different in the 2 cases. Chemical attack and molecular modeling experiments have indicated that the acceptor end of tRNA(Tyr) ... CCCA3'-OH, remains mobile after the initial binding of tRNA(Tyr) to TyrTS.
在本综述中，我汇集并比较了有关原核生物来源的tRNA（Tyr）与酪氨酰 - tRNA合成酶（TyrTS）之间相互作用的现有数据。能够使大肠杆菌tRNA（Tyr）氨酰化的异源TyrTS的氨基酸序列表明，参与酪氨酸结合和识别的残基严格保守，而参与与tRNA（Tyr）相互作用的残基仅具有微弱的相似性。体内遗传互补实验结果表明，tRNA的识别元件以及合成酶对这些元件的识别机制在进化过程中得以保留。异源或突变的tRNA（Tyr）可被大肠杆菌TyrTS定量氨酰化；如果排除tRNA的不变和半不变残基，它们的共同残基集合包含少于10个元件。该集合中的残基是TyrTS特异性识别的候选者。到目前为止，腺苷 - 73是唯一已被证明对碱基有特异性识别的残基。可能作为大肠杆菌tRNA（Tyr）识别元件的残基[McClain WH，Nicholas Jr HB（1987）J Mol Biol 194，635 - 642]不属于上述保守残基集合，因此可能起负面作用，使tRNA（Tyr）避免与非同源合成酶结合。对突变型tRNA（Tyr）su +3的氨酰化和稳定性特性的比较表明，碱基1和72必须配对（通过沃森 - 克里克或非经典氢键）并采用与受体茎螺旋结构兼容的几何形状，以便突变型tRNA（Tyr）能够被酪氨酰化。如果碱基1和72或碱基2和71不能形成这种配对，突变型tRNA（Tyr）su +3的抑制子表型就会变为温度敏感型。通过突变削弱碱基对1/72或将腺苷 - 73变为鸟苷会导致tRNA（Tyr）su +3被谷氨酰胺氨酰化。TyrTS/tRNA（Tyr）复合物的结构模型与GlnTS/tRNA（Gln）复合物的晶体结构的比较表明，在这两种情况下，受体臂的识别机制不同。化学攻击和分子模拟实验表明，tRNA（Tyr）... CCCA3'-OH的受体末端在tRNA（Tyr）与TyrTS初始结合后仍保持可移动性。
