Structural basis for translation termination on the 70S ribosome
Structural basis for translation termination on the 70S ribosome
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DOI：
10.1038/nature07115
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发表时间：
2008-08-14
期刊：
影响因子：
64.8
通讯作者：
Noller, Harry F.
中科院分区：
文献类型：
--
作者：
Laurberg, Martin;Asahara, Haruichi;Noller, Harry F.
在蛋白质合成终止时，I型释放因子促进肽基转移RNA连接的水解，以响应终止密码子的识别。在这里，我们描述了Thermus thermophilus 70S核糖体的晶体结构，它与释放因子RF1、tRNA和含有UAA终止密码子的信使RNA形成复合体，分辨率为3.2埃。终止密码子在RF1的保守元件(包括其PXT识别基序)和16S核糖体RNA形成的口袋中被识别。密码子和30S亚基A位点经历诱导配对，导致RF1的构象稳定，促进其与肽基转移酶中心的相互作用。出乎意料的是，在该因子的普遍保守的GGQ基序中，谷氨酰胺230的主链酰胺基团被定位为直接促进肽-tRNA的水解。
At termination of protein synthesis, type I release factors promote hydrolysis of the peptidyl-transfer RNA linkage in response to recognition of a stop codon. Here we describe the crystal structure of the Thermus thermophilus 70S ribosome in complex with the release factor RF1, tRNA and a messenger RNA containing a UAA stop codon, at 3.2 angstrom resolution. The stop codon is recognized in a pocket formed by conserved elements of RF1, including its PxT recognition motif, and 16S ribosomal RNA. The codon and the 30S subunit A site undergo an induced fit that results in stabilization of a conformation of RF1 that promotes its interaction with the peptidyl transferase centre. Unexpectedly, the main-chain amide group of Gln 230 in the universally conserved GGQ motif of the factor is positioned to contribute directly to peptidyl-tRNA hydrolysis.