The structure of elongation factor G in complex with GDP: Conformational flexibility and nucleotide exchange
The structure of elongation factor G in complex with GDP: Conformational flexibility and nucleotide exchange
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DOI：
10.1016/s0969-2126(96)00061-5
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发表时间：
1996-05-15
期刊：
影响因子：
5.7
通讯作者：
Liljas, A
中科院分区：
文献类型：
--
作者：
Al-Karadaghi, S;AEvarsson, A;Liljas, A
背景：延伸因子G（EF-G）催化翻译的易位步骤。在移位过程中，EF-G通过四种主要的构象状态：GDP复合物、无核苷酸状态、GTP复合物和GTP酶构象。前两个这些构象已被先前调查的晶体学methods.Results：EF-G-GDP的结构已被细化到2.4埃分辨率。与无核苷酸结构的比较表明，GDP释放后，磷酸结合环（P-环）采用闭合构象。这影响螺旋C-G、开关II环和结构域II、IV和V的位置。Asp 83具有与EF-Tu/EF-Ts复合物中相应残基的构象相似的构象。结论：EF-G-GDP的P环构象变化可以传递到结构的其他部分，EF-G和EF-Tu的结构比较表明EF-G和EF-Tu一样，也经历了结构域重排的转变，EF-G-GDP在核苷酸结合位点附近的构象可能与核苷酸交换机制有关。
Background: Elongation factor G (EF-G) catalyzes the translocation step of translation. During translocation EF-G passes through four main conformational states: the GDP complex, the nucleotide-free state, the GTP complex, and the GTPase conformation. The first two of these conformations have been previously investigated by crystallographic methods.Results: The structure of EF-G-GDP has been refined at 2.4 Angstrom resolution. Comparison with the nucleotide-free structure reveals that, upon GDP release, the phosphate-binding loop (P-loop) adopts a closed conformation. This affects the position of helix C-G, the switch II loop and domains II, IV and V. Asp83 has a conformation similar to the conformation of the corresponding residue in the EF-Tu/EF-Ts complex. The magnesium ion is absent in EF-G-GDP.Conclusions: The results illustrate that conformational changes in the P-loop can be transmitted to other parts of the structure, A comparison of the structures of EF-G and EF-Tu suggests that EF-G, like EF-Tu, undergoes a transition with domain rearrangements, The conformation of EF-G GDP around the nucleotide-binding site may be related to the mechanism of nucleotide exchange.