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首页> 外文期刊>Genes to cells : >RMF inactivates ribosomes by covering the peptidyl transferase centre and entrance of peptide exit tunnel.
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RMF inactivates ribosomes by covering the peptidyl transferase centre and entrance of peptide exit tunnel.

机译：RMF通过覆盖肽基转移酶中心和肽出口通道的入口来灭活核糖体。

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摘要

In gram-negative bacteria such as Escherichia coli, protein synthesis is suppressed by the formation of 100S ribosomes under stress conditions. The 100S ribosome, a dimer of 70S ribosomes, is formed by ribosome modulation factor (RMF) binding to the 70S ribosomes. During the stationary phase, most of the 70S ribosomes turn to 100S ribosomes, which have lost translational activity. This 100S formation is called the hibernation process in the ribosome cycle of the stationary phase. If stationary phase cells are transferred to fresh medium, the 100S ribosomes immediately go back to active 70S ribosomes, showing that inactive 100S <--> active 70S interconversion is a major system regulating translation activity in stationary phase cells. To elucidate the mechanisms of translational inactivation, the binding sites of RMF on 23S rRNA in 100S ribosome of E. coli were examined by a chemical probing method using dimethyl sulphate (DMS). As the results, the nine bases in 23S rRNA were protected from DMS modifications and the modification of one base was enhanced. Interestingly A2451 is included among the protected bases, which is thought to be directly involved in peptidyl transferase activity. We conclude that RMF inactivates ribosomes by covering the peptidyl transferase (PTase) centre and the entrance of peptide exit tunnel. It is surprising that the cell itself produces a protein that seems to inhibit protein synthesis in a similar manner to antibiotics and that it can reversibly bind to and release from the ribosome in response to environmental conditions.
机译：在革兰氏阴性细菌（例如大肠杆菌）中，蛋白质合成受到应激条件下100S核糖体的形成的抑制。 100S核糖体是70S核糖体的二聚体，由结合到70S核糖体的核糖体调节因子（RMF）形成。在稳定期，大多数70S核糖体会转变为100S核糖体，而后者失去了翻译活性。这种100S的形成称为固定相核糖体循环中的冬眠过程。如果将固定相细胞转移到新鲜培养基中，则100S核糖体会立即回到有活性的70S核糖体，这表明无活性的100S→有活性的70S相互转化是调节固定相细胞中翻译活性的主要系统。为了阐明翻译失活的机制，通过使用硫酸二甲酯（DMS）的化学探测方法检查了RMF在大肠杆菌100S核糖体中23S rRNA上的结合位点。结果，保护了23S rRNA中的9个碱基免受DMS修饰，并增强了1个碱基的修饰。有趣的是，A2451包括在受保护的碱基中，被认为直接参与肽基转移酶的活性。我们得出的结论是，RMF通过覆盖肽基转移酶（PTase）中心和肽出口通道的入口来灭活核糖体。令人惊讶的是，细胞自身产生的蛋白质似乎以与抗生素相似的方式抑制蛋白质的合成，并且它可以响应于环境条件而可逆地结合至核糖体并从核糖体中释放。

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