Elongation Factor Ts Directly Facilitates the Formation and Disassembly of the Escherichia coli Elongation Factor Tu•GTP•Aminoacyl-tRNA Ternary Complex
Elongation Factor Ts Directly Facilitates the Formation and Disassembly of the Escherichia coli Elongation Factor Tu•GTP•Aminoacyl-tRNA Ternary Complex
复制标题
DOI：
10.1074/jbc.m113.460014
复制
发表时间：
2013-05-10
影响因子：
4.8
通讯作者：
Blanchard, Scott C.
中科院分区：
文献类型：
--
作者：
Burnett, Benjamin J.;Altman, Roger B.;Blanchard, Scott C.
氨酰-tRNA与延伸因子Tu（EF-Tu）和GTP形成三元复合物进入翻译核糖体。在这里，我们描述了散装稳态和预稳态荧光方法，使我们能够定量探索大肠杆菌三元复合物的形成和衰变的动力学特征。所获得的数据表明，这两个过程是由一个核苷酸依赖性，速率决定EF-Tu的构象变化。出乎意料的是，我们发现这种构象变化是加速延长因子Ts（EF-Ts），EF-Tu的鸟苷酸交换因子。值得注意的是，EF-Ts减弱EF-Tu对GTP的亲和力，并在不可水解的GTP类似物存在下使三元复合物不稳定。这些结果表明，EF-Ts在细胞中发挥了意想不到的作用，以有助于快速和忠实的蛋白质合成的方式积极调节三元复合物的丰度和稳定性。
Aminoacyl-tRNA enters the translating ribosome in a ternary complex with elongation factor Tu (EF-Tu) and GTP. Here, we describe bulk steady state and pre-steady state fluorescence methods that enabled us to quantitatively explore the kinetic features of Escherichia coli ternary complex formation and decay. The data obtained suggest that both processes are controlled by a nucleotide-dependent, rate-determining conformational change in EF-Tu. Unexpectedly, we found that this conformational change is accelerated by elongation factor Ts (EF-Ts), the guanosine nucleotide exchange factor for EF-Tu. Notably, EF-Ts attenuates the affinity of EF-Tu for GTP and destabilizes ternary complex in the presence of non-hydrolyzable GTP analogs. These results suggest that EF-Ts serves an unanticipated role in the cell of actively regulating the abundance and stability of ternary complex in a manner that contributes to rapid and faithful protein synthesis.