據(jù)發(fā)表于10月16日Science雜志的一篇研究報(bào)告,，劍橋大學(xué)分子生物學(xué)實(shí)驗(yàn)室由Venki Ramakrishnan主持的研究小組首次獲得核糖體與延伸因子(elongation factor G,EF-G)結(jié)合的圖片,。
EF-G是一種參與蛋白質(zhì)生物合成中多肽鏈延伸過(guò)程的移位酶。研究人員對(duì)一種采集自海底火山口的耐熱菌的核糖體進(jìn)行研究,，他們將核糖體進(jìn)行純化,，然后加入一種聚合物，該聚合物能夠使多個(gè)核糖體線(xiàn)性連接并形成晶體結(jié)構(gòu),，此外研究人員還加入一種名為夫西地酸(fusidic acid)的抗生素,，該抗生素能使EF-G連接到核糖體上。
之前研究人員試圖使EF-G與核糖體一起進(jìn)行結(jié)晶,，但結(jié)果出現(xiàn)EF-G被其他核糖體取代下來(lái)。據(jù)Dunham介紹,，之后研究人員對(duì)核糖體進(jìn)行部分切割后,，才使EF-G結(jié)合到核糖體上。
研究人員利用X射線(xiàn)分析了核糖體與EF-G結(jié)合形成的晶體,，并通過(guò)X射線(xiàn)數(shù)據(jù)研究該晶體的結(jié)構(gòu),。Dunham在該研究報(bào)告中描述了EF-G與核糖體相互作用的詳細(xì)過(guò)程。此外,，該報(bào)告還對(duì)研究核糖體與其他類(lèi)似于EF-G的蛋白之間的相互作用提供了新信息,。（生物谷Bioon.com）
生物谷推薦原始出處：
Science October 15, 2009 DOI: 10.1126/science.1179709
The Structure of the Ribosome with Elongation Factor G Trapped in the Posttranslocational State
Yong-Gui Gao 1, Maria Selmer 2, Christine M. Dunham 3, Albert Weixlbaumer 4, Ann C. Kelley 1, V. Ramakrishnan 1*
1 MRC Laboratory of Molecular Biology, Hills Road, Cambridge, CB2 0QH, UK.
2 MRC Laboratory of Molecular Biology, Hills Road, Cambridge, CB2 0QH, UK.; Present address: Department of Cell and Molecular Biology, Uppsala University, Box 596, Uppsala, SE 751 24, Sweden.
3 MRC Laboratory of Molecular Biology, Hills Road, Cambridge, CB2 0QH, UK.; Present address: Department of Biochemistry, Emory University School of Medicine, Atlanta GA 30322, USA.
4 MRC Laboratory of Molecular Biology, Hills Road, Cambridge, CB2 0QH, UK.; Present address: The Rockefeller University, Box 224, New York NY 10065, USA.
* To whom correspondence should be addressed.
Elongation factor G (EF-G) is a guanosine triphosphatase (GTPase) that plays a crucial role in the translocation of transfer RNAs (tRNAs) and messenger RNA (mRNA) during translation by the ribosome. We report a crystal structure refined to 3.6 angstrom resolution of the ribosome trapped with EF-G in the posttranslocational state using the antibiotic fusidic acid. Fusidic acid traps EF-G in a conformation intermediate between the guanosine triphosphate and guanosine diphosphate forms. The interaction of EF-G with ribosomal elements implicated in stimulating catalysis, such as the L10-L12 stalk and the L11 region, and of domain IV of EF-G with the tRNA at the peptidyl-tRNA binding site (P site) and with mRNA shed light on the role of these elements in EF-G function in catalysis and translocation. The stabilization of the mobile stalks of the ribosome also results in a more complete description of its structure.
