Department of Biology and Biochemistry, University of Houston, 4800 Calhoun Rd, Houston, TX 77214, USA.
Biophys Chem. 2012 Jun;167:8-15. doi: 10.1016/j.bpc.2012.04.003. Epub 2012 May 7.
The movement of peptidyl tRNA into the P-site after ribosome translocation reduces the ribosome dynamics in the post-translocation complex, which "locks" the ribosome to less conformational fluctuations. Here, we used single molecule FRET method to reveal that ribosomes bearing L27 with N-terminal truncations are less competent to "lock" the tRNA fluctuations after translocation. We found that: (1) truncation of the first three N-terminal residues of L27 increases peptidyl tRNA fluctuation; and (2) increasing the solution pH increases peptidyl tRNA fluctuation in WT and some of the ribosome mutants. We propose that one role of L27 at the catalytic center is to stabilize peptidyl tRNA in the post-translocation complex.
核糖体转位后肽酰 tRNA 进入 P 位会降低翻译后复合物中核糖体的动力学，从而“锁定”核糖体，使其构象波动减少。在这里，我们使用单分子 FRET 方法揭示了带有 N 端截断的 L27 的核糖体在转位后“锁定” tRNA 波动的能力较弱。我们发现：（1）L27 的前三个 N 端残基的截断会增加肽酰 tRNA 的波动；（2）增加溶液 pH 值会增加 WT 和一些核糖体突变体中的肽酰 tRNA 波动。我们提出，L27 在催化中心的作用之一是稳定翻译后复合物中的肽酰 tRNA。
