Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Mol Cell. 2013 Feb 7;49(3):427-38. doi: 10.1016/j.molcel.2012.11.025. Epub 2012 Dec 27.
Quality control of ribosomes is critical for cellular function since protein mistranslation leads to severe physiological consequences. We report evidence of a previously unrecognized ribosome quality control system in bacteria that operates at the level of 70S to remove defective ribosomes. YbeY, a previously unidentified endoribonuclease, and the exonuclease RNase R act together by a process mediated specifically by the 30S ribosomal subunit, to degrade defective 70S ribosomes but not properly matured 70S ribosomes or individual subunits. Furthermore, there is essentially no fully matured 16S rRNA in a ΔybeY mutant at 45°C, making YbeY the only endoribonuclease to be implicated in the critically important processing of the 16S rRNA 3' terminus. These key roles in ribosome quality control and maturation indicate why YbeY is a member of the minimal bacterial gene set and suggest that it could be a potential target for antibacterial drugs.
核糖体的质量控制对于细胞功能至关重要，因为蛋白质翻译错误会导致严重的生理后果。我们报告了一种以前未被识别的细菌核糖体质量控制体系的证据，该体系在 70S 水平上起作用，以去除有缺陷的核糖体。YbeY 是一种以前未被识别的内切核酸酶，与外切核酸酶 RNase R 一起通过一个由 30S 核糖体亚基特异性介导的过程发挥作用，以降解有缺陷的 70S 核糖体，但不降解成熟的 70S 核糖体或单个亚基。此外，在 45°C 时，ΔybeY 突变体中基本上没有完全成熟的 16S rRNA，这使得 YbeY 成为唯一一种被牵连到 16S rRNA 3'端关键加工过程的内切核酸酶。YbeY 在核糖体质量控制和成熟方面的这些关键作用表明了它为什么是最小细菌基因集的成员，并表明它可能是一种潜在的抗菌药物靶标。
