Interactions of release factor RF3 with the translation machinery
Interactions of release factor RF3 with the translation machinery
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释放因子 RF3 与翻译机制的相互作用
DOI：
10.1007/s00438-015-0994-x
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发表时间：
2015
影响因子：
3.1
通讯作者：
M. O’Connor
中科院分区：
文献类型：
--
作者：
M. O’Connor
细菌释放因子RF 3是一种涉及蛋白质合成的多个不完全理解的步骤的GT酶。本研究探讨了RF 3与翻译机制的其他组成部分的遗传相互作用。RF 3通过将I类释放因子RF 1和RF 2从终止后核糖体中回收来促进翻译终止。RF 3还涉及肽基-tRNA从延长核糖体的解离，以及肽基转移酶后质量控制（PT后QC）机制，其选择性终止携带错误肽的核糖体。大多数关于RF 3的体内研究是在大肠杆菌的K-12菌株中进行的，该菌株携带在246位具有Ala至Thr取代的部分缺陷的RF 2蛋白。在这里，K-12特异性RF 2变体对RF 3活性的贡献进行了研究。菌株重构实验表明，E.大肠杆菌和肠道沙门氏菌的研究表明，当不完全活性的K-12特异性RF 2蛋白被完全活性的Ala 246 RF 2替代时，与RF 3丢失相关的终止和PT后QC中的缺陷以及表型分析未发现的表型都得到了显著改善。这些结果表明，RF 3的损失是耐受性良好的细菌具有完全活性的I类释放因子，但许多先前报道的表型RF 3缺失菌株已受到损害的存在下，部分缺陷的RF 2。
The bacterial release factor RF3 is a GTPase that has been implicated in multiple, incompletely understood steps of protein synthesis. This study explores the genetic interaction of RF3 with other components of the translation machinery. RF3 contributes to translation termination by recycling the class I release factors RF1 and RF2 off post-termination ribosomes. RF3 has also been implicated in dissociation of peptidyl-tRNAs from elongating ribosomes and in a post-peptidyltransferase quality control (post-PT QC) mechanism that selectively terminates ribosomes carrying erroneous peptides. A majority of the in vivo studies on RF3 have been carried out in K-12 strains of Escherichia coli which carry a partially defective RF2 protein with an Ala to Thr substitution at position 246. Here, the contribution of the K-12 specific RF2 variant to RF3 activities has been investigated. Strain reconstruction experiments in both E. coli and Salmonellaenterica demonstrate that defects in termination and post-PT QC that are associated with RF3 loss, as well as phenotypes uncovered by phenotypic profiling, are all substantially ameliorated when the incompletely active K-12-specific RF2 protein is replaced by a fully active Ala246 RF2. These results indicate that RF3 loss is well tolerated in bacteria with fully active class I release factors, but that many of the previously reported phenotypes for RF3 deletion strains have been compromised by the presence of a partially defective RF2.