Control of phosphate release from elongation factor G by ribosomal protein L7/12.

Andreas Savelsbergh, Dagmar Mohr, Ute Kothe, Wolfgang Wintermeyer, Marina V Rodnina

Institute of Molecular Biology, University of Witten/Herdecke, Witten, Germany.

The EMBO journal 2005 Dec 21

filter terms:

Ribosomal protein L7/12 is crucial for the function of elongation factor G (EF-G) on the ribosome. Here, we report the localization of a site in the C-terminal domain (CTD) of L7/12 that is critical for the interaction with EF-G. Single conserved surface amino acids were replaced in the CTD of L7/12. Whereas mutations in helices 5 and 6 had no effect, replacements of V66, I69, K70, and R73 in helix 4 increased the Michaelis constant (KM) of EF-G.GTP for the ribosome, suggesting an involvement of these residues in EF-G binding. The mutations did not appreciably affect rapid single-round GTP hydrolysis and had no effect on tRNA translocation on the ribosome. In contrast, the release of inorganic phosphate (Pi) from ribosome-bound EF-G.GDP.Pi was strongly inhibited and became rate-limiting for the turnover of EF-G. The control of Pi release by interactions between EF-G and L7/12 appears to be important for maintaining the conformational coupling between EF-G and the ribosome for translocation and for timing the dissociation of the factor from the ribosome.

Citation

Andreas Savelsbergh, Dagmar Mohr, Ute Kothe, Wolfgang Wintermeyer, Marina V Rodnina. Control of phosphate release from elongation factor G by ribosomal protein L7/12. The EMBO journal. 2005 Dec 21;24(24):4316-23