Release factor RF3 in E-coli accelerates the dissociation of release factors RF1 and RF2 from the ribosome in a GTP-dependent manner
Release factor RF3 in E-coli accelerates the dissociation of release factors RF1 and RF2 from the ribosome in a GTP-dependent manner
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DOI：
10.1093/emboj/16.13.4126
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发表时间：
1997-07-01
期刊：
影响因子：
11.4
通讯作者：
Ehrenberg, M
中科院分区：
文献类型：
--
作者：
Freistroffer, DV;Pavlov, MY;Ehrenberg, M
与合成的mRNA和肽基-tRNA复合的核糖体，准备肽释放，通过凝胶过滤纯化，并用于研究释放因子RF 3和鸟嘌呤核苷酸在蛋白质合成终止中的功能。的肽释放活性的RF 1和RF 2在限制浓度的刺激通过添加RF 3和GTP，刺激，虽然在较小程度上，由RF 3和一个非水解GTP类似物，并抑制RF 3和GDP或RF 3没有鸟嘌呤核苷酸。由于短的孵育时间仅允许RF 1或RF 2的单个催化循环，肽释放活性不依赖于RF 3和鸟嘌呤核苷酸。GTP至GDP + Pi的RF 3水解仅依赖于核糖体，而不依赖于RF 1或RF 2。RF 3既不影响RF 1和RF 2与核糖体的结合速率，也不影响肽释放的催化速率。提出了一个模型，它解释了如何RF 3取代RF 1和RF 2从核糖体的肽释放后的因素。
Ribosomes complexed with synthetic mRNA and peptidyl-tRNA, ready for peptide release, were purified by gel filtration and used to study the function of release factor RF3 and guanine nucleotides in the termination of protein synthesis. The peptide-releasing activity of RF1 and RF2 in limiting concentrations was stimulated by the addition of RF3 and GTP, stimulated, though to a lesser extent, by RF3 and a non-hydrolysable GTP analogue, and inhibited by RF3 and GDP or RF3 without guanine nucleotide. With short incubation times allowing only a single catalytic cycle of RF1 or RF2, peptide release activity was independent of RF3 and guanine nucleotide. RF3 hydrolysis of GTP to GDP + P-i was dependent only on ribosomes and not oh RF1 or RF2. RF3 affected neither the rate of association of RF1 and RF2 with the ribosome nor the catalytic rate of peptide release. A model is proposed which explains how RF3 recycles RF1 and RF2 by displacing the factors from the ribosome after the release of peptide.