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| [[Image:1tui.gif|left|200px]] | | [[Image:1tui.png|left|200px]] |
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| ==Overview==
| | {{ABSTRACT_8939739}} |
| BACKGROUND: Elongation factor Tu (EF-Tu) in its GTP conformation is a carrier of aminoacylated tRNAs (aa-tRNAs) to the ribosomal A site during protein biosynthesis. The ribosome triggers GTP hydrolysis, resulting in the dissociation of EF-Tu-GDP from the ribosome. The affinity of EF-Tu for other molecules involved in this process, some of which are unknown, is regulated by two regions (Switch I and Switch II) that have different conformations in the GTP and GDP forms. The structure of the GDP form of EF-Tu is known only as a trypsin-modified fragment, which lacks the Switch I, or effector, domain. The aim of this work was to establish the overall structure of intact EF-Tu-GDP, in particular the structure of the effector domain. RESULTS: The crystal structures of intact EF-Tu-GDP from Thermus aquaticus and Escherichia coli have been determined at resolutions of 2.7 A and 3.8 A, respectively. The structures confirm the domain orientation previously found in the structure of partially trypsin-digested EF-Tu-GDP. The structures of the effector region in T. aquaticus and E. coli EF-Tu-GDP are very similar. The C-terminal part of the effector region of EF-Tu-GDP is a beta hairpin; in EF-Tu-GTP, this region forms an alpha helix. This conformational change is not a consequence of crystal packing. CONCLUSIONS: EF-Tu undergoes major conformational changes upon GTP hydrolysis. Unlike other GTP-binding proteins, EF-Tu exhibits a dramatic conformational change in the effector region, involving an unwinding of a small helix and the formation of a beta hairpin structure. This change is presumably involved in triggering the release of tRNA, and EF-Tu, from the ribosome.
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| ==About this Structure== | | ==About this Structure== |
| 1TUI is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Thermus_aquaticus Thermus aquaticus]. The following page contains interesting information on the relation of 1TUI with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb81_1.html Elongation Factors]]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1TUI OCA]. | | 1TUI is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Thermus_aquaticus Thermus aquaticus]. The following page contains interesting information on the relation of 1TUI with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb81_1.html Elongation Factors]]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1TUI OCA]. |
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| ==Reference==
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| Helix unwinding in the effector region of elongation factor EF-Tu-GDP., Polekhina G, Thirup S, Kjeldgaard M, Nissen P, Lippmann C, Nyborg J, Structure. 1996 Oct 15;4(10):1141-51. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/8939739 8939739]
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| [[Category: Elongation Factors]] | | [[Category: Elongation Factors]] |
| [[Category: Single protein]] | | [[Category: Single protein]] |
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| [[Category: Gtp-binding]] | | [[Category: Gtp-binding]] |
| [[Category: Protein biosynthesis]] | | [[Category: Protein biosynthesis]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 10:22:53 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Jun 26 18:02:18 2008'' |
