The pretranslocation ribosome is targeted by GTP-bound EF-G in partially activated form
(2008) In Proceedings of the National Academy of Sciences of the United States of America 105(41). p.15678-15683- Abstract
Translocation of the tRNA·mRNA complex through the bacterial ribosome is driven by the multidomain guanosine triphosphatase elongation factor G (EF-G). We have used isothermal titration calorimetry to characterize the binding of GDP and GTP to free EF-G at 4°C, 20°C, and 37°C. The binding affinity of EF-G is higher to GDP than to GTP at 4°C, but lower at 37°C. The binding enthalpy and entropy change little with temperature in the case of GDP binding but change greatly in the case of GTP binding. These observations are compatible with a large decrease in the solvent-accessible hydrophobic surface area of EF-G on GTP, but not GDP, binding. The explanation we propose is the locking of the switch 1 and switch 2 peptide loops in the G domain... (More)
Translocation of the tRNA·mRNA complex through the bacterial ribosome is driven by the multidomain guanosine triphosphatase elongation factor G (EF-G). We have used isothermal titration calorimetry to characterize the binding of GDP and GTP to free EF-G at 4°C, 20°C, and 37°C. The binding affinity of EF-G is higher to GDP than to GTP at 4°C, but lower at 37°C. The binding enthalpy and entropy change little with temperature in the case of GDP binding but change greatly in the case of GTP binding. These observations are compatible with a large decrease in the solvent-accessible hydrophobic surface area of EF-G on GTP, but not GDP, binding. The explanation we propose is the locking of the switch 1 and switch 2 peptide loops in the G domain of EF-G to the γ-phosphate of GTP. From these data, in conjunction with previously reported structural data on guanine nucleotide-bound EF-G, we suggest that EF-G enters the pretranslocation ribosome as an "activity chimera," with the G domain activated by the presence of GTP but the overall factor conformation in the inactive form typical of a GDP-bound multidomain guanosine triphosphatase. We propose that the active overall conformation of EF-G is attained only in complex with the ribosome in its "ratcheted state," with hybrid tRNA binding sites.
(Less)
- author
- Hauryliuk, Vasili
LU
; Mitkevich, Vladimir A. ; Eliseeva, Natalia A. ; Petrushanko, Irina Yu ; Ehrenberg, Måns and Makarov, Alexander A.
- publishing date
- 2008-10-14
- type
- Contribution to journal
- publication status
- published
- keywords
- GTPase, Guanine nucleotide binding, Isothermal titration calorimetry, Thermodynamic parameters of interaction
- in
- Proceedings of the National Academy of Sciences of the United States of America
- volume
- 105
- issue
- 41
- pages
- 6 pages
- publisher
- National Academy of Sciences
- external identifiers
-
- pmid:18836081
- scopus:57349132462
- ISSN
- 0027-8424
- DOI
- 10.1073/pnas.0807912105
- language
- English
- LU publication?
- no
- additional info
- Copyright: Copyright 2019 Elsevier B.V., All rights reserved.
- id
- e79f33dc-d7ac-457d-bc5f-cbb3664e9ebc
- date added to LUP
- 2021-09-24 20:50:48
- date last changed
- 2024-06-01 17:06:01
@article{e79f33dc-d7ac-457d-bc5f-cbb3664e9ebc, abstract = {{<p>Translocation of the tRNA·mRNA complex through the bacterial ribosome is driven by the multidomain guanosine triphosphatase elongation factor G (EF-G). We have used isothermal titration calorimetry to characterize the binding of GDP and GTP to free EF-G at 4°C, 20°C, and 37°C. The binding affinity of EF-G is higher to GDP than to GTP at 4°C, but lower at 37°C. The binding enthalpy and entropy change little with temperature in the case of GDP binding but change greatly in the case of GTP binding. These observations are compatible with a large decrease in the solvent-accessible hydrophobic surface area of EF-G on GTP, but not GDP, binding. The explanation we propose is the locking of the switch 1 and switch 2 peptide loops in the G domain of EF-G to the γ-phosphate of GTP. From these data, in conjunction with previously reported structural data on guanine nucleotide-bound EF-G, we suggest that EF-G enters the pretranslocation ribosome as an "activity chimera," with the G domain activated by the presence of GTP but the overall factor conformation in the inactive form typical of a GDP-bound multidomain guanosine triphosphatase. We propose that the active overall conformation of EF-G is attained only in complex with the ribosome in its "ratcheted state," with hybrid tRNA binding sites.</p>}}, author = {{Hauryliuk, Vasili and Mitkevich, Vladimir A. and Eliseeva, Natalia A. and Petrushanko, Irina Yu and Ehrenberg, Måns and Makarov, Alexander A.}}, issn = {{0027-8424}}, keywords = {{GTPase; Guanine nucleotide binding; Isothermal titration calorimetry; Thermodynamic parameters of interaction}}, language = {{eng}}, month = {{10}}, number = {{41}}, pages = {{15678--15683}}, publisher = {{National Academy of Sciences}}, series = {{Proceedings of the National Academy of Sciences of the United States of America}}, title = {{The pretranslocation ribosome is targeted by GTP-bound EF-G in partially activated form}}, url = {{http://dx.doi.org/10.1073/pnas.0807912105}}, doi = {{10.1073/pnas.0807912105}}, volume = {{105}}, year = {{2008}}, }