Guanine-nucleotide exchange on ribosome-bound elongation factor G initiates the translocation of tRNAs
(2005) In Journal of Biology 4.- Abstract
Background. During the translation of mRNA into polypeptide, elongation factor G (EF-G) catalyzes the translocation of peptidyl-tRNA from the A site to the P site of the ribosome. According to the 'classical' model, EF-G in the GTP-bound form promotes translocation, while hydrolysis of the bound GTP promotes dissociation of the factor from the post-translocation ribosome. According to a more recent model, EF-G operates like a 'motor protein' and drives translocation of the peptidyl-tRNA after GTP hydrolysis. In both the classical and motor protein models, GDP-to-GTP exchange is assumed to occur spontaneously on 'free' EF-G even in the absence of a guanine-nucleotide exchange factor (GEF). Results. We have made a number of findings that... (More)
Background. During the translation of mRNA into polypeptide, elongation factor G (EF-G) catalyzes the translocation of peptidyl-tRNA from the A site to the P site of the ribosome. According to the 'classical' model, EF-G in the GTP-bound form promotes translocation, while hydrolysis of the bound GTP promotes dissociation of the factor from the post-translocation ribosome. According to a more recent model, EF-G operates like a 'motor protein' and drives translocation of the peptidyl-tRNA after GTP hydrolysis. In both the classical and motor protein models, GDP-to-GTP exchange is assumed to occur spontaneously on 'free' EF-G even in the absence of a guanine-nucleotide exchange factor (GEF). Results. We have made a number of findings that challenge both models. First, free EF-G in the cell is likely to be in the GDP-bound form. Second, the ribosome acts as the GEF for EF-G. Third, after guanine-nucleotide exchange, EF-G in the GTP-bound form moves the tRNA2-mRNA complex to an intermediate translocation state in which the mRNA is partially translocated. Fourth, subsequent accommodation of the tRNA2-mRNA complex in the post-translocation state requires GTP hydrolysis. Conclusion. These results, in conjunction with previously published cryo-electron microscopy reconstructions of the ribosome in various functional states, suggest a novel mechanism for translocation of tRNAs on the ribosome by EF-G. Our observations suggest that the ribosome is a universal guanosine-nucleotide exchange factor for EF-G as previously shown for the class-II peptide-release factor 3.
(Less)
- author
- Zavialov, Andrey V. ; Hauryliuk, Vasili V. LU and Ehrenberg, M̊ns
- publishing date
- 2005
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of Biology
- volume
- 4
- article number
- 9
- publisher
- BioMed Central (BMC)
- external identifiers
-
- pmid:15985150
- scopus:20444393817
- ISSN
- 1478-5854
- DOI
- 10.1186/jbiol24
- language
- English
- LU publication?
- no
- additional info
- Copyright: Copyright 2008 Elsevier B.V., All rights reserved.
- id
- 0a5c1a7b-6c01-4f08-b381-3197e1b1e58e
- date added to LUP
- 2021-09-24 20:54:04
- date last changed
- 2024-04-06 10:35:26
@article{0a5c1a7b-6c01-4f08-b381-3197e1b1e58e, abstract = {{<p>Background. During the translation of mRNA into polypeptide, elongation factor G (EF-G) catalyzes the translocation of peptidyl-tRNA from the A site to the P site of the ribosome. According to the 'classical' model, EF-G in the GTP-bound form promotes translocation, while hydrolysis of the bound GTP promotes dissociation of the factor from the post-translocation ribosome. According to a more recent model, EF-G operates like a 'motor protein' and drives translocation of the peptidyl-tRNA after GTP hydrolysis. In both the classical and motor protein models, GDP-to-GTP exchange is assumed to occur spontaneously on 'free' EF-G even in the absence of a guanine-nucleotide exchange factor (GEF). Results. We have made a number of findings that challenge both models. First, free EF-G in the cell is likely to be in the GDP-bound form. Second, the ribosome acts as the GEF for EF-G. Third, after guanine-nucleotide exchange, EF-G in the GTP-bound form moves the tRNA2-mRNA complex to an intermediate translocation state in which the mRNA is partially translocated. Fourth, subsequent accommodation of the tRNA2-mRNA complex in the post-translocation state requires GTP hydrolysis. Conclusion. These results, in conjunction with previously published cryo-electron microscopy reconstructions of the ribosome in various functional states, suggest a novel mechanism for translocation of tRNAs on the ribosome by EF-G. Our observations suggest that the ribosome is a universal guanosine-nucleotide exchange factor for EF-G as previously shown for the class-II peptide-release factor 3.</p>}}, author = {{Zavialov, Andrey V. and Hauryliuk, Vasili V. and Ehrenberg, M̊ns}}, issn = {{1478-5854}}, language = {{eng}}, publisher = {{BioMed Central (BMC)}}, series = {{Journal of Biology}}, title = {{Guanine-nucleotide exchange on ribosome-bound elongation factor G initiates the translocation of tRNAs}}, url = {{http://dx.doi.org/10.1186/jbiol24}}, doi = {{10.1186/jbiol24}}, volume = {{4}}, year = {{2005}}, }