THE CRYSTAL-STRUCTURE OF ELONGATION-FACTOR EF-TU FROM THERMUS-AQUATICUS IN THE GTP CONFORMATION
THE CRYSTAL-STRUCTURE OF ELONGATION-FACTOR EF-TU FROM THERMUS-AQUATICUS IN THE GTP CONFORMATION
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DOI：
10.1016/0969-2126(93)90007-4
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发表时间：
1993-09-15
期刊：
影响因子：
5.7
通讯作者：
NYBORG, J
中科院分区：
文献类型：
--
作者：
KJELDGAARD, M;NISSEN, P;NYBORG, J
背景：延伸因子Tu （EF-Tu）是一种gtp结合蛋白，对蛋白质的生物合成至关重要。在GTP形式的分子中，EF-Tu与氨基酰基- trnq紧密结合，形成与核糖体受体位点相互作用的三元复合物。在这种相互作用中，GTP被水解，EF-Tu。GDP被排除在外。结果：在2.5埃的分辨率下，测定了与GTP类似物GDPNP配合的水热菌EF-Tu的晶体结构，并与大肠杆菌EF-Tu. gdp的结构进行了比较。在从GDP（非活性）到GTP（活性）形式的转变过程中，包含GTP结合位点的结构域1经历了与ras-p21相似的内部构象变化。此外，还观察到结构域的戏剧性重排，对应于结构域1相对于结构域2和3旋转了90.8度。在氨基酰基- trna结合过程中受到影响的残基位于结构域界面形成的间隙内或附近。结论：EF-Tu结合GTP可引起显著构象变化，暴露tRNA结合位点。似乎tRNA结合EF-Tu诱导进一步的构象变化，这可能影响GTPase的活性。
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.