Localization of L11 protein on the ribosome and elucidation of its involvement in EF-G-dependent translocation
Localization of L11 protein on the ribosome and elucidation of its involvement in EF-G-dependent translocation
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DOI：
10.1006/jmbi.2001.4907
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发表时间：
2001-08-24
影响因子：
5.6
通讯作者：
Frank, J
中科院分区：
文献类型：
--
作者：
Agrawal, RK;Linde, J;Frank, J
L11蛋白位于大肠杆菌核糖体50个S亚基的L7/LI2茎的碱基上。由于该区域的灵活性，最近对50个S亚基的X射线结晶学研究未能定位该蛋白的N-末端结构域。我们通过将从缺乏核糖体蛋白L11的突变体中分离出来的70个S核糖体的三维冷冻EM重建与野生型核糖体的三维图谱进行比较，确定了完整L11蛋白的位置。将L11-23 S RNA复合体和EF-G的X射线坐标拟合到冷冻-EM图中，结合分子模拟，揭示了EF-G依赖的GTP水解后，EF-G的V结构域侵入了23 S核糖体RNA和L11的N-末端结构域(抗生素硫链菌素结合的地方)之间的裂隙，导致N-末端结构域移动，从而诱导与EF-G的G‘结构域形成弧形连接。这一结果为探讨EF-G依赖易位的机制提供了新的思路。
L11 protein is located at the base of the L7/LI2 stalk of the 50 S subunit of the Escherichia coli ribosome. Because of the flexible nature of the region, recent X-ray crystallographic studies of the 50 S subunit failed to locate the N-terminal domain of the protein. We have determined the position of the complete L11 protein by comparing a three-dimensional cryo-EM reconstruction of the 70 S ribosome, isolated from a mutant lacking ribosomal protein L11, with the three-dimensional map of the wild-type ribosome. Fitting of the X-ray coordinates of L11-23 S RNA complex and EF-G into the cryo-EM maps combined with molecular modeling, reveals that, following EF-G-dependent GTP hydrolysis, domain V of EF-G intrudes into the cleft between the 23 S ribosomal RNA and the N-terminal domain of L11 (where the antibiotic thiostrepton binds), causing the N-terminal domain to move and thereby inducing the formation of the arc-like connection with the G' domain of EF-G. The results provide a new insight into the mechanism of EF-G-depenclent translocation.