Burnett Benjamin J, Altman Roger B, Ferguson Angelica, Wasserman Michael R, Zhou Zhou, Blanchard Scott C
From the Department of Physiology and Biophysics and.
Tri-Institutional Program in Chemical Biology, Weill Cornell Medical College, New York, New York 10065.
J Biol Chem. 2014 Aug 22;289(34):23917-27. doi: 10.1074/jbc.M114.583385. Epub 2014 Jul 2.
During protein synthesis, elongation factor-Tu (EF-Tu) bound to GTP chaperones the entry of aminoacyl-tRNA (aa-tRNA) into actively translating ribosomes. In so doing, EF-Tu increases the rate and fidelity of the translation mechanism. Recent evidence suggests that EF-Ts, the guanosine nucleotide exchange factor for EF-Tu, directly accelerates both the formation and dissociation of the EF-Tu-GTP-Phe-tRNA(Phe) ternary complex (Burnett, B. J., Altman, R. B., Ferrao, R., Alejo, J. L., Kaur, N., Kanji, J., and Blanchard, S. C. (2013) J. Biol. Chem. 288, 13917-13928). A central feature of this model is the existence of a quaternary complex of EF-Tu/Ts·GTP·aa-tRNA(aa). Here, through comparative investigations of phenylalanyl, methionyl, and arginyl ternary complexes, and the development of a strategy to monitor their formation and decay using fluorescence resonance energy transfer, we reveal the generality of this newly described EF-Ts function and the first direct evidence of the transient quaternary complex species. These findings suggest that EF-Ts may regulate ternary complex abundance in the cell through mechanisms that are distinct from its guanosine nucleotide exchange factor functions.
在蛋白质合成过程中，与鸟苷三磷酸（GTP）结合的延伸因子-Tu（EF-Tu）辅助氨酰-tRNA（aa-tRNA）进入正在进行翻译的核糖体。在此过程中，EF-Tu提高了翻译机制的速率和保真度。最近的证据表明，EF-Tu的鸟苷核苷酸交换因子EF-Ts可直接加速EF-Tu-GTP-苯丙氨酰-tRNA（Phe）三元复合物的形成和解离（伯内特，B.J.，阿尔特曼，R.B.，费劳，R.，阿莱霍，J.L.，考尔，N.，坎吉，J.，和布兰查德，S.C.（2013年）《生物化学杂志》288卷，13917 - 13928页）。该模型的一个核心特征是存在EF-Tu/Ts·GTP·aa-tRNA（aa）四元复合物。在这里，通过对苯丙氨酰、甲硫氨酰和精氨酰三元复合物的比较研究，以及开发一种利用荧光共振能量转移监测它们形成和衰变的策略，我们揭示了这种新描述的EF-Ts功能的普遍性以及瞬态四元复合物物种的首个直接证据。这些发现表明，EF-Ts可能通过与其鸟苷核苷酸交换因子功能不同的机制来调节细胞中三元复合物的丰度。
