An elongation factor G-induced ribosome rearrangement precedes tRNA-mRNA translocation.
The elongation cycle of protein synthesis is completed by translocation, a rearrangement during which two tRNAs bound to the mRNA move on the ribosome. The reaction is promoted by elongation factor G (EF-G) and accelerated by GTP hydrolysis. Here we report a pre-steady-state kinetic analysis of translocation. The kinetic model suggests that GTP hydrolysis drives a conformational rearrangement of the ribosome that precedes and limits the rates of tRNA-mRNA translocation and Pi release from EF-G.GDP.Pi. The latter two steps are intrinsically rapid and take place at random. These results indicate that the energy of GTP hydrolysis is utilized to promote the ribosome rearrangement and to bias spontaneous fluctuations within the ribosome-EF-G complex toward unidirectional movement of mRNA and tRNA.
Savelsbergh
Andreas
A
Institute of Molecular Biology, University of Witten/Herdecke, 58448 Witten, Germany.
Katunin
Vladimir I
VI
Mohr
Dagmar
D
Peske
Frank
F
Rodnina
Marina V
MV
Wintermeyer
Wolfgang
W
D000818:Animals; D004734:Energy Metabolism; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D008954:Models, Biological; D020653:Peptide Elongation Factor G / Q000235:genetics / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D012343:RNA, Transfer / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014178:Translocation, Genetic
D020653:Peptide Elongation Factor G; D010710:Phosphates; D012333:RNA, Messenger; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D012343:RNA, Transfer