EF-G Activation by Phosphate Analogs. Issue 10 (22nd May 2016)

• Record Type: Journal Article
• Authors: Salsi, Enea; Farah, Elie; Ermolenko, Dmitri N.
• Is Part Of: Journal of molecular biology. Volume 428:Issue 10:Part B(2016:May 15)
• Page Start: 2248
• Page End: 2258
• Publication Date: 2016-05-22
• Subjects: Ribosome -- EF-G -- mRNA translocation -- GTP hydrolysis -- Beryllium fluoride; EF-G elongation factor G -- Pi inorganic phosphate; Molecular biology -- Periodicals; Biology -- Periodicals; Biochemistry -- Periodicals; Bacteriology -- Periodicals; Molecular Biology -- Periodicals; Biochemistry -- Periodicals; Biologie moléculaire -- Périodiques; Biologie -- Périodiques; Biochimie -- Périodiques; Moleculaire biologie; Biochemistry; Biology; Molecular biology; Periodicals; 572.805
• DOI: 10.1016/j.jmb.2016.03.032
• Languages: English
• ISSNs: 0022-2836

Abstract

Abstract: Elongation factor G (EF-G) is a universally conserved translational GTPase that promotes the translocation of tRNA and mRNA through the ribosome. EF-G binds to the ribosome in a GTP-bound form and subsequently catalyzes GTP hydrolysis. The contribution of the ribosome-stimulated GTP hydrolysis by EF-G to tRNA/mRNA translocation remains debated. Here, we show that while EF-GGDP does not stably bind to the ribosome and induce translocation, EF-GGDP in complex with phosphate group analogs BeF3 − and AlF4 − promotes the translocation of tRNA and mRNA. Furthermore, the rates of mRNA translocation induced by EF-G in the presence of GTP and a non-hydrolyzable analog of GTP, GDPBeF3 − are similar. Our results are consistent with the model suggesting that GTP hydrolysis is not directly coupled to mRNA/tRNA translocation. Hence, GTP binding is required to induce the activated, translocation-competent conformation of EF-G while GTP hydrolysis triggers EF-G release from the ribosome. Graphical Abstract: Highlights: GDPBeF3 − and GDPAlF4 − trap EF-G bound to the ribosome. EF-GGDPBeF3 − and EF-GGDPAlF4 − promote mRNA translocation. The rates of mRNA translocation induced by EF-GGTP and EF-GGDPBeF3 − are similar. GTP hydrolysis is not directly involved in promoting mRNA/tRNA translocation.