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 tran...

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Bibliographic Details
Published in:Molecular cell 2003-06, Vol.11 (6), p.1517-1523
Main Authors: Savelsbergh, Andreas, Katunin, Vladimir I., Mohr, Dagmar, Peske, Frank, Rodnina, Marina V., Wintermeyer, Wolfgang
Format: Article
Language:English
Subjects:
Animals
Energy Metabolism
Guanosine Diphosphate - metabolism
Guanosine Triphosphate - metabolism
Humans
Hydrolysis
Kinetics
Models, Biological
Peptide Elongation Factor G - genetics
Peptide Elongation Factor G - metabolism
Phosphates - metabolism
Ribosomes - chemistry
Ribosomes - genetics
Ribosomes - metabolism
RNA, Messenger - genetics
RNA, Messenger - metabolism
RNA, Transfer - genetics
RNA, Transfer - metabolism
Time Factors
Translocation, Genetic
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Summary: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.
ISSN:1097-2765
1097-4164
DOI:10.1016/S1097-2765(03)00230-2