title: EF-G Activation by Phosphate Analogs.
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-G•GDP does not stably bind to the ribosome and induce translocation, EF-G•GDP 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, GDP•BeF3(-) 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.
authors.affiliation: Department of Biochemistry and Biophysics & Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA.
authors.forename: Enea
authors.initials: E
authors.lastname: Salsi
authors.affiliation: Department of Biochemistry and Biophysics & Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA.
authors.forename: Elie
authors.initials: E
authors.lastname: Farah
authors.affiliation: Department of Biochemistry and Biophysics & Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA. Electronic address: Dmitri_Ermolenko@urmc.rochester.edu.
authors.forename: Dmitri N
authors.initials: DN
authors.lastname: Ermolenko
mesh_terms: D017607:Aluminum Compounds / Q000494:pharmacology; D001880:Boranes / Q000494:pharmacology; D005459:Fluorides / Q000494:pharmacology; D020558:GTP Phosphohydrolases / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006868:Hydrolysis / Q000187:drug effects; D020653:Peptide Elongation Factor G / Q000378:metabolism*; D010710:Phosphates / Q000494:pharmacology*; D014176:Protein Biosynthesis / Q000187:drug effects*; D012333:RNA, Messenger / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism; D012270:Ribosomes / Q000187:drug effects*
chemical_list: D017607:Aluminum Compounds; D001880:Boranes; D020653:Peptide Elongation Factor G; D010710:Phosphates; D012333:RNA, Messenger; C050992:tetrafluoroaluminate; C021274:boron trifluoride; D006160:Guanosine Triphosphate; D012343:RNA, Transfer; D020558:GTP Phosphohydrolases; D005459:Fluorides
keywords: Beryllium fluoride; EF-G; GTP hydrolysis; Ribosome; mRNA translocation