Entropic Contribution of Elongation Factor P to Pro line Positioning at the Catalytic Center of the Ribosome
Entropic Contribution of Elongation Factor P to Pro line Positioning at the Catalytic Center of the Ribosome
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DOI：
10.1021/jacs.5b07427
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发表时间：
2015-10-14
影响因子：
15
通讯作者：
Rodnina, Marina V.
中科院分区：
文献类型：
--
作者：
Doerfel, Lili K.;Wohlgemuth, Ingo;Rodnina, Marina V.
与核糖体上的氨基酸脯氨酸（Pro）的肽键形成是缓慢的，当必须将几个Pro掺入肽中时导致翻译停滞。在聚-Pro基序处的停滞通过延伸因子P（EF-P）减轻。在这里，我们调查为什么Pro是一个穷人的基板和EF-P如何催化反应。核糖体上的反应和在溶液中使用12种不同的Pro类似物的线性自由能关系表明，在肽基转移酶中心的前-tRNA的定位是缓慢反应的主要决定因素。对于测试的任何Pro类似物，EF-P将反应的活化能降低了几乎均匀的2.5 kcal/mol的值。催化的主要来源是EF-P带来的有利的熵变。因此，EF-P通过熵引导Pro-tRNA朝向核糖体的肽基转移酶中心中的催化生产方向而起作用。
The peptide bond formation with the amino acid praline (Pro) on the ribosome is slow, resulting in translational stalling when several Pro have to be incorporated into the peptide. Stalling at poly-Pro motifs is alleviated by the elongation factor P (EF-P). Here we investigate why Pro is a poor substrate and how EF-P catalyzes the reaction. Linear free energy relationships of the reaction on the ribosome and in solution using 12 different Pro analogues suggest that the positioning of Pro-tRNA in the peptidyl transferase center is the major determinant for the slow reaction. With any Pro analogue tested, EF-P decreases the activation energy of the reaction by an almost uniform value of 2.5 kcal/mol. The main source of catalysis is the favorable entropy change brought about by EF-P. Thus, EF-P acts by entropic steering of Pro-tRNA toward a catalytically productive orientation in the peptidyl transferase center of the ribosome.