THE CRYSTAL-STRUCTURE OF ELONGATION-FACTOR EF-TU FROM THERMUS-AQUATICUS IN THE GTP CONFORMATION

被引:367
作者
KJELDGAARD, M
NISSEN, P
THIRUP, S
NYBORG, J
机构
[1] Department of Chemistry, Aarhus University, DK-8000 Århus C
关键词
CONFORMATIONAL CHANGE; ELONGATION FACTOR; G-PROTEIN; PROTEIN BIOSYNTHESIS; X-RAY STRUCTURE;
D O I
10.1016/0969-2126(93)90007-4
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Background: Elongation factor Tu (EF-Tu) is a GTP-binding protein that is crucial for protein biosynthesis. In the GTP form of the molecule, EF-Tu binds tightly to aminoacyl-tRNq forming a ternary complex that interacts with the ribosomal acceptor site. During this interaction, GTP is hydrolyzed, and EF-Tu.GDP is ejected. Results: The crystal structure of EF-Tu from Thermus aquaticus, complexed to the GTP analogue GDPNP, has been determined at 2.5 Angstrom resolution and compared to the structure of Escherichia coli EF-Tu.GDP. During the transition from the GDP (inactive) to the GTP (active) form, domain 1, containing the GTP-binding site, undergoes internal conformational changes similar to those observed in ras-p21. in addition, a dramatic rearrange ment of domains is observed, corresponding to a rotation of 90.8 degrees of domain 1 relative to domains 2 and 3. Residues that are affected in the binding of aminoacyl-tRNA are found in or near the cleft formed by the domain interface. Conclusion: GTP binding by EF-Tu leads to dramatic conformational changes which expose the tRNA binding site. It appears that tRNA binding to EF-Tu induces a further conformational change, which may affect the GTPase activity.
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页码:35 / 50
页数:16
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