不稳定的RNA结构由大肠杆菌的DEAD-box陪伴者拆卸加速了核糖体组装
Yunsheng Sun1, Sarah A Woodson1
1T.C. Jenkins Department of Biophysics, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, United States.
Nucleic acids research
|February 23, 2025
概括
死亡盒蛋白CsdA有助于新生细菌核糖体RNA (rRNA) 正确折叠,加速关键核糖体蛋白质的结合. 这种伴侣介导的不稳定结构的展开引导了适当的核糖体组装.
科学领域:
- 细菌分子生物学 细菌分子生物学
- 核糖体生物生成 (Ribosome Biogenesis) 是一个过程.
- RNA折叠的动力学
背景情况:
- 细菌核糖体合成涉及合转录和核糖体前RNA (pre-rRNA) 的折叠.
- 在转录过程中细菌前-16S rRNA的错误折叠可以阻碍核糖体蛋白 uS4 的结合,延迟 16S 5' 域组装.
研究的目的:
- 为了研究DEAD-box蛋白CsdA在细菌核糖体组装中的作用.
- 阐明CsdA如何促进新生rRNA的正确折叠和蛋白质结合.
主要方法:
- 使用单分子光显微镜实时观察rRNA-蛋白相互作用.
- 研究了CsdA对细菌16S前rRNA和核糖体蛋白S4的折叠和结合动态的影响.
主要成果:
- 通过促进新生rRNA的正确折叠,CsdA显著加快了核糖体蛋白 uS4 的结合.
- CsdA可以展开不稳定的RNA结构,但对稳定的结构或随着更多的核糖体蛋白质结合而变得不太有效.
- 随着核糖体蛋白质在rRNA上聚集的进展,CsdA介导的展开的频率下降.
结论:
- 不稳定的RNA-蛋白质复合体的辅助分解对于推动寻找原生rRNA结构至关重要.
- 像CsdA这样的一般伴侣建立了分解梯度,确保了对核糖体蛋白质的正确等级添加.
- 这一过程促进了后期组装中间体的30S核糖体子单元成熟的承诺.
相关概念视频
Ribosomal RNA Synthesis
13.1K
Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
13.1K
Improving Translational Accuracy
8.5K
Base complementarity between the three base pairs of mRNA codon and the tRNA anticodon is not a failsafe mechanism. Inaccuracies can range from a single mismatch to no correct base pairing at all. The free energy difference between the correct and nearly correct base pairs can be as small as 3 kcal/ mol. With complementarity being the only proofreading step, the estimated error frequency would be one wrong amino acid in every 100 amino acids incorporated. However, error frequencies observed in...
8.5K
Termination of Translation
24.8K
The large ribosomal subunit has several important structures essential to translation. These include the peptidyl transferase center (PTC) - which is the site where the peptide bond is formed - and a large, internal, water-filled tube through which the nascent polypeptide moves. This latter structure is called the Peptide Exit Tunnel, and it begins at the PTC and spans the body of the large ribosomal subunit. During translation, as the nascent polypeptide chain is synthesized, it passes through...
24.8K
Molecular Chaperones and Protein Folding
17.7K
The native conformation of a protein is formed by interactions between the side chains of its constituent amino acids. When the amino acids cannot form these interactions, the protein cannot fold by itself and needs chaperones. Notably, chaperones do not relay any additional information required for the folding of polypeptides; the native conformation of a protein is determined solely by its amino acid sequence. Chaperones catalyze protein folding without being a part of the folded protein.
The...
The...
17.7K
Nonsense-mediated mRNA Decay
10.4K
The Upf proteins that carry out nonsense-mediated decay (NMD) are found in all eukaryotic organisms, including humans. Each protein has an individual role, but they need to work in collaboration. Upf1 is an ATP-dependent RNA helicase that unwinds the RNA helix. Because Upf1 can unwind any RNA, Upf2 and Upf3 are required to help Upf1 discriminate between nonsense and normal mRNAs.
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
10.4K
mRNA Stability and Gene Expression
5.5K
The structure and stability of mRNA molecules regulates gene expression, as mRNAs are a key step in the pathway from gene to protein. In eukaryotes, the half-life of mRNA varies from a few minutes up to several days. mRNA stability is essential in growth and development. The absence of the proteins regulating its stability, such as tristetraprolin in mice, can cause systemic issues, including bone marrow overgrowth, inflammation, and autoimmunity.
Cis-acting Elements involved in mRNA stability
Cis-acting Elements involved in mRNA stability
5.5K


