Szewczak A A, Moore P B
Department of Chemistry and Molecular Biophysics, Yale University, New Haven, CT 06520.
J Mol Biol. 1995 Mar 17;247(1):81-98. doi: 10.1006/jmbi.1994.0124.
The conformation of a 29 base oligonucleotide called E73 has been determined in solution by NMR. E73 includes a 23 nucleotide sequence that is identical with that of a the alpha-sarcin and ricin-sensitive loop (SRL) from rat 28 S rRNA, and like the SRL in intact ribosomes, E73 is a substrate for both toxins. The SRL includes a long, conserved sequence found in the RNA of all large ribosomal subunits, which plays a critical role in the factor-dependent steps of protein synthesis. The spectroscopic observations and analysis that led to the determination of the conformation of E73 are presented. The SRL in E73 has a highly structured conformation, which is stabilized by several non-Watson-Crick base-pairs, and many properties of the SRL in the ribosome can be understood assuming that the conformation of E73 and that of the SRL in the ribosome are the same. The role of the SRL in protein synthesis is discussed in light of the conformation of E73, as is the modular relationship that exists between the conformation of the SRL and other smaller RNAs.
一种名为E73的29个碱基的寡核苷酸在溶液中的构象已通过核磁共振（NMR）确定。E73包含一个23个核苷酸的序列，该序列与大鼠28S rRNA的α-肌动蛋白和蓖麻毒素敏感环（SRL）的序列相同，并且与完整核糖体中的SRL一样，E73是这两种毒素的底物。SRL包含一个在所有大核糖体亚基的RNA中都存在的长保守序列，该序列在蛋白质合成的因子依赖性步骤中起关键作用。本文介绍了导致确定E73构象的光谱观察和分析。E73中的SRL具有高度结构化的构象，该构象由几个非沃森-克里克碱基对稳定，并且假设E73的构象与核糖体中SRL的构象相同，就可以理解核糖体中SRL的许多特性。本文根据E73的构象讨论了SRL在蛋白质合成中的作用，以及SRL的构象与其他较小RNA之间存在的模块化关系。
