Alternative conformations and motions adopted by 30S ribosomal subunits visualized by cryo-electron microscopy.
Alternative conformations and motions adopted by 30S ribosomal subunits visualized by cryo-electron microscopy.
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DOI：
10.1261/rna.075846.120
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发表时间：
2020-12
期刊：
影响因子：
--
通讯作者：
Ortega J
中科院分区：
文献类型：
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作者：
Jahagirdar D;Jha V;Basu K;Gomez-Blanco J;Vargas J;Ortega J
只有在低温电子显微镜的最新进展之后，才有可能以高分辨率描述不结晶的大分子结构。纯化的30 S亚基在“活性”和“非活性”构象之间相互转化。活性构象在21世纪初由晶体学描述，但高分辨率的非活性形式的结构仍然没有解决。在这里，我们使用冷冻电子显微镜获得的30 S亚基的非活性构象的结构，以3.6纳米分辨率，并研究其运动。在非活性构象中，三个核苷酸的替代碱基配对导致形成解码中心的螺旋44区域采取未闩锁构象，并且16 S rRNA的3′端位置与翻译期间的mRNA相似。在42°C下孵育失活的30 S亚基可以逆转这些结构变化。在样品制备过程中，核糖体亚基所暴露的空气-水界面也会剥离一些核糖体蛋白。长期暴露于低镁浓度使核糖体颗粒更容易受到空气-水界面的影响，导致大rRNA结构域的展开。总的来说，这项研究提供了新的见解的构象空间探索的30 S核糖体亚基时，核糖体颗粒在溶液中是免费的。
It is only after recent advances in cryo-electron microscopy that it is now possible to describe at high-resolution structures of large macromolecules that do not crystalize. Purified 30S subunits interconvert between an “active” and “inactive” conformation. The active conformation was described by crystallography in the early 2000s, but the structure of the inactive form at high resolution remains unsolved. Here we used cryo-electron microscopy to obtain the structure of the inactive conformation of the 30S subunit to 3.6 Å resolution and study its motions. In the inactive conformation, an alternative base-pairing of three nucleotides causes the region of helix 44, forming the decoding center to adopt an unlatched conformation and the 3′ end of the 16S rRNA positions similarly to the mRNA during translation. Incubation of inactive 30S subunits at 42°C reverts these structural changes. The air–water interface to which ribosome subunits are exposed during sample preparation also peel off some ribosomal proteins. Extended exposures to low magnesium concentrations make the ribosomal particles more susceptible to the air–water interface causing the unfolding of large rRNA structural domains. Overall, this study provides new insights about the conformational space explored by the 30S ribosomal subunit when the ribosomal particles are free in solution.
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影响因子：
14.9
作者：
López-Alonso JP;Kaminishi T;Kikuchi T;Hirata Y;Iturrioz I;Dhimole N;Schedlbauer A;Hase Y;Goto S;Kurita D;Muto A;Zhou S;Naoe C;Mills DJ;Gil-Carton D;Takemoto C;Himeno H;Fucini P;Connell SR
通讯作者：
Connell SR
影响因子：
3.2
作者：
Daigle, DM;Brown, ED
通讯作者：
Brown, ED
DOI：
10.1093/bioinformatics/btp250
发表时间：
2009-08-01
期刊：
Bioinformatics (Oxford, England)
影响因子：
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作者：
Darty K;Denise A;Ponty Y
通讯作者：
Ponty Y
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
大肠杆菌K-12的构造框架，单基因敲除突变体：Keio Collection。
影响因子：
9.9
作者：
通讯作者：
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