Cochella Luisa, Green Rachel
Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Science. 2005 May 20;308(5725):1178-80. doi: 10.1126/science.1111408.
During transfer RNA (tRNA) selection, a cognate codon:anticodon interaction triggers a series of events that ultimately results in the acceptance of that tRNA into the ribosome for peptide-bond formation. High-fidelity discrimination between the cognate tRNA and near- and noncognate ones depends both on their differential dissociation rates from the ribosome and on specific acceleration of forward rate constants by cognate species. Here we show that a mutant tRNA(Trp) carrying a single substitution in its D-arm achieves elevated levels of miscoding by accelerating these forward rate constants independent of codon:anticodon pairing in the decoding center. These data provide evidence for a direct role for tRNA in signaling its own acceptance during decoding and support its fundamental role during the evolution of protein synthesis.
在转运RNA（tRNA）选择过程中，同源密码子：反密码子相互作用引发一系列事件，最终导致该tRNA被核糖体接受以形成肽键。同源tRNA与近同源和非同源tRNA之间的高保真区分既取决于它们从核糖体的不同解离速率，也取决于同源物种对正向速率常数的特异性加速。在这里，我们表明，在其D臂中携带单个取代的突变型tRNA（Trp）通过加速这些正向速率常数实现了错义编码水平的提高，而这与解码中心的密码子：反密码子配对无关。这些数据为tRNA在解码过程中直接发出自身被接受的信号提供了证据，并支持其在蛋白质合成进化过程中的基本作用。
