一张30S核糖体亚基通过Shine-Dalgarno相互作用捕获mRNA的快照。

A snapshot of the 30S ribosomal subunit capturing mRNA via the Shine-Dalgarno interaction.

作者信息

Kaminishi Tatsuya, Wilson Daniel N, Takemoto Chie, Harms Joerg M, Kawazoe Masahito, Schluenzen Frank, Hanawa-Suetsugu Kyoko, Shirouzu Mikako, Fucini Paola, Yokoyama Shigeyuki

机构信息

RIKEN Genomic Sciences Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan.

出版信息

Structure. 2007 Mar;15(3):289-97. doi: 10.1016/j.str.2006.12.008.

DOI:10.1016/j.str.2006.12.008

PMID:17355865

Abstract

In the initiation phase of bacterial translation, the 30S ribosomal subunit captures mRNA in preparation for binding with initiator tRNA. The purine-rich Shine-Dalgarno (SD) sequence, in the 5' untranslated region of the mRNA, anchors the 30S subunit near the start codon, via base pairing with an anti-SD (aSD) sequence at the 3' terminus of 16S rRNA. Here, we present the 3.3 A crystal structure of the Thermus thermophilus 30S subunit bound with an mRNA mimic. The duplex formed by the SD and aSD sequences is snugly docked in a "chamber" between the head and platform domains, demonstrating how the 30S subunit captures and stabilizes the otherwise labile SD helix. This location of the SD helix is suitable for the placement of the start codon AUG in the immediate vicinity of the mRNA channel, in agreement with reported crosslinks between the second position of the start codon and G1530 of 16S rRNA.

摘要

在细菌翻译的起始阶段，30S核糖体亚基捕获mRNA，为与起始tRNA结合做准备。mRNA 5'非翻译区富含嘌呤的Shine-Dalgarno（SD）序列，通过与16S rRNA 3'末端的反SD（aSD）序列碱基配对，将30S亚基锚定在起始密码子附近。在此，我们展示了嗜热栖热菌30S亚基与mRNA模拟物结合的3.3埃晶体结构。由SD和aSD序列形成的双链体紧密对接在头部和平台结构域之间的“腔室”中，展示了30S亚基如何捕获并稳定原本不稳定的SD螺旋。SD螺旋的这一位置适合将起始密码子AUG放置在mRNA通道的紧邻位置，这与报道的起始密码子第二位与16S rRNA的G1530之间的交联一致。