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arXiv · 0909.0466

Allosteric collaboration between elongation factor G and the ribosomal L1 stalk directs tRNA movements during translation

Jingyi Fei·Jonathan E. Bronson·Jake M. Hofman·Rathi L. Srinivas·Chris H. Wiggins·Ruben L. Gonzalez, Jr
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Abstract

Determining the mechanism by which transfer RNAs (tRNAs) rapidly and precisely transit through the ribosomal A, P and E sites during translation remains a major goal in the study of protein synthesis. Here, we report the real-time dynamics of the L1 stalk, a structural element of the large ribosomal subunit that is implicated in directing tRNA movements during translation. Within pre-translocation ribosomal complexes, the L1 stalk exists in a dynamic equilibrium between open and closed conformations. Binding of elongation factor G (EF-G) shifts this equilibrium towards the closed conformation through one of at least two distinct kinetic mechanisms, where the identity of the P-site tRNA dictates the kinetic route that is taken. Within post-translocation complexes, L1 stalk dynamics are dependent on the presence and identity of the E-site tRNA. Collectively, our data demonstrate that EF-G and the L1 stalk allosterically collaborate to direct tRNA translocation from the P to the E sites, and suggest a model for the release of E-site tRNA.

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Jingyi Fei, Jonathan E. Bronson, Jake M. Hofman, Rathi L. Srinivas, Chris H. Wiggins, Ruben L. Gonzalez, Jr. 2009-09-02. Allosteric collaboration between elongation factor G and the ribosomal L1 stalk directs tRNA movements during translation. https://doi.org/10.1073/pnas.0908077106

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