据介绍，蛋白质合成始于核糖体-信使RNA（mRNA）复合物的形成。在细菌中，小核糖体亚基（30S）通过与Shine-Dalgarno（SD）序列的碱基配对和核糖体蛋白bS1的RNA结合被招募到许多mRNA中。翻译可以在新生的mRNA上启动，RNA聚合酶（RNAP）可以促进先导30S的招募。
研究人员使用冷冻电镜、单分子荧光共定位和细胞内交联质谱检查了新生mRNA的30S募集。研究人员发现bS1将mRNA传递到核糖体，形成SD双链体并激活30S。此外，bS1和RNAP刺激翻译启动。
总之，这一工作为SD双链体、核糖体蛋白和RNAP如何在mRNA的30S募集中合作，并建立转录-翻译偶联提供了一个机制框架。
附：英文原文
Title: Molecular basis of mRNA delivery to the bacterial ribosome
Author: Michael W. Webster, Adrien Chauvier, Huma Rahil, Andrea Graziadei, Kristine Charles, Nataliya Miropolskaya, Maria Takacs, Charlotte Saint-André, Juri Rappsilber, Nils G. Walter, Albert Weixlbaumer
Issue&Volume: 2024-11-29
Abstract: Protein synthesis begins with the formation of a ribosome-messenger RNA (mRNA) complex. In bacteria, the small ribosomal subunit (30S) is recruited to many mRNAs through base pairing with the Shine-Dalgarno (SD) sequence and RNA binding by ribosomal protein bS1. Translation can initiate on nascent mRNAs, and RNA polymerase (RNAP) can promote the recruitment of the pioneering 30S. Here, we examined 30S recruitment to nascent mRNAs using cryo–electron microscopy, single-molecule fluorescence colocalization, and in-cell cross-linking mass spectrometry. We show that bS1 delivers the mRNA to the ribosome for SD duplex formation and 30S activation. Additionally, bS1 and RNAP stimulate translation initiation. Our work provides a mechanistic framework for how the SD duplex, ribosomal proteins, and RNAP cooperate in 30S recruitment to mRNAs and establish transcription-translation coupling.
DOI: ado8476
Source: https://www.science.org/doi/10.1126/science.ado8476