RbfA Is Involved in Two Important Stages of 30S Subunit Assembly: Formation of the Central Pseudoknot and Docking of Helix 44 to the Decoding Center.
RbfA Is Involved in Two Important Stages of 30S Subunit Assembly: Formation of the Central Pseudoknot and Docking of Helix 44 to the Decoding Center.
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DOI：
10.3390/ijms22116140
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发表时间：
2021-06-07
影响因子：
5.6
通讯作者：
Stolboushkina EA
中科院分区：
文献类型：
--
作者：
Maksimova EM;Korepanov AP;Kravchenko OV;Baymukhametov TN;Myasnikov AG;Vassilenko KS;Afonina ZA;Stolboushkina EA
核糖体生物发生是一个高度协调和复杂的过程，需要大量的组装因子来确保核糖体亚基迅速和完美的成熟。尽管收集到的数据量越来越大，但大多数组装因子的确切作用及其运作的机制细节仍然不清楚，主要是由于缺乏高分辨率的结构信息。在这里，使用冷冻电子显微镜，我们鉴定了从一株缺失RbfA因子基因的大肠杆菌菌株中分离出的30S核糖体颗粒。30S前亚基的冷冻-EM图谱分为六类，对应于连续的组装中间产物：从头部结构域完全未分解、中央伪结未折叠的颗粒到几乎成熟的30S亚基，主体、平台和头部结构域分辨良好，螺旋44部分扭曲。在2.7ä分辨率下获得的属于大多数填充类的两个主要30s中间体的结构表明，RbfA在两个不同的30s组装阶段发挥作用：中央伪结的早期形成包括头部的折叠，以及后期螺旋44在解码中心的定位。此外，研究表明，中心假结的形成可能促进头部结构域的稳定，可能是通过依赖于RbfA的颈部螺旋28的成熟。对因子依赖的30S成熟模型进行了更新，表明RfbA参与了大部分亚基的组装过程。
Ribosome biogenesis is a highly coordinated and complex process that requires numerous assembly factors that ensure prompt and flawless maturation of ribosomal subunits. Despite the increasing amount of data collected, the exact role of most assembly factors and mechanistic details of their operation remain unclear, mainly due to the shortage of high-resolution structural information. Here, using cryo-electron microscopy, we characterized 30S ribosomal particles isolated from an Escherichia coli strain with a deleted gene for the RbfA factor. The cryo-EM maps for pre-30S subunits were divided into six classes corresponding to consecutive assembly intermediates: from the particles with a completely unresolved head domain and unfolded central pseudoknot to almost mature 30S subunits with well-resolved body, platform, and head domains and partially distorted helix 44. The structures of two predominant 30S intermediates belonging to most populated classes obtained at 2.7 Å resolutions indicate that RbfA acts at two distinctive 30S assembly stages: early formation of the central pseudoknot including folding of the head, and positioning of helix 44 in the decoding center at a later stage. Additionally, it was shown that the formation of the central pseudoknot may promote stabilization of the head domain, likely through the RbfA-dependent maturation of the neck helix 28. An update to the model of factor-dependent 30S maturation is proposed, suggesting that RfbA is involved in most of the subunit assembly process.
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DOI：
10.1261/rna.075846.120
发表时间：
2020-12
期刊：
RNA (New York, N.Y.)
影响因子：
--
作者：
Jahagirdar D;Jha V;Basu K;Gomez-Blanco J;Vargas J;Ortega J
通讯作者：
Ortega J
影响因子：
10.5
作者：
DAMMEL, CS;NOLLER, HF
通讯作者：
NOLLER, HF
影响因子：
4.5
作者：
Gulati M;Jain N;Davis JH;Williamson JR;Britton RA
通讯作者：
Britton RA
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
5.6
作者：
Huang, YPJ;Swapna, GVT;Montelione, GT
通讯作者：
Montelione, GT