Single amino acid substitution in prokaryote polypeptide release factor 2 permits it to terminate translation at all three stop codons
Single amino acid substitution in prokaryote polypeptide release factor 2 permits it to terminate translation at all three stop codons
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DOI：
10.1073/pnas.95.14.8165
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发表时间：
1998-07-07
影响因子：
11.1
通讯作者：
Nakamura, Y
中科院分区：
文献类型：
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作者：
Ito, K;Uno, M;Nakamura, Y
前体翻译释放因子RF 1和RF 2分别在UAG/UAA和UGA/UAA终止密码子处催化多肽释放。在这项研究中，我们分离出一个细菌RF 2突变体（RF 2 *）含有E167 K取代恢复的温度敏感性大肠杆菌RF 1菌株的生长和染色体RF 1/RF 2双敲除的活力。在体内和体外多肽终止测定中，RF 2 * 催化UAG/UAA终止，RF 1也是如此，以及UGA终止，表明RF 2 * 获得全能释放活性。该结果表明E167 K突变消除了RF 2的推定的第三个碱基终止功能，这些发现被解释为表明原核和真核释放因子共享相同的反密码子部分，并且只有一种全能释放因子足以用于细菌生长，类似真核生物的单一全能因子。
Prokaryotic translational release factors, RF1 and RF2, catalyze polypeptide release at UAG/UAA and UGA/UAA stop codons, respectively. In this study, we isolated a bacterial RF2 mutant (RF2*) containing an E167K substitution that restored the growth of a temperature-sensitive RF1 strain of Escherichia coli and the viability of a chromosomal RF1/RF2 double knockout. In both in vivo and in vitro polypeptide termination assays, RF2* catalyzed UAG/UAA termination, as does RF1, as well as UGA termination, showing that RF2* acquired omnipotent release activity, This result suggests that the E167K mutation abolished the putative third-base discriminator function of RF2, These findings are interpreted as indicating that prokaryotic and eukaryotic release factors share the same anticodon moiety and that only one omnipotent release factor is sufficient for bacterial growth, similar to the eukaryotic single omnipotent factor.