Ganoza M C, Vandermeer J, Debreceni N, Phillips S L
Proc Natl Acad Sci U S A. 1973 Jan;70(1):31-5. doi: 10.1073/pnas.70.1.31.
Mutant N4316 is conditionally lethal at 43 degrees . At 36 degrees it suppresses the termination codons UGA and UAA, but not the UAG codon or a missense mutant of T4 bacteriophage. In vitro, a factor rescues protein synthesis from a temperature-dependent arrest when N4316 extracts are used with RNA from bacteriophage f2. Analyses of the substrate in the arrested synthesis and of the product of the rescue reaction indicate that the factor works at the level of coat protein termination, and that it also affects the synthesis of noncoat protein products. The rescue factor is different from the release factors RF-1, RF-2, and RF-3. Model systems previously used to study release fail to score for at least one vital function in protein chain termination.
突变体N4316在43摄氏度时具有条件致死性。在36摄氏度时，它能抑制终止密码子UGA和UAA，但不能抑制UAG密码子或T4噬菌体的错义突变体。在体外，当将N4316提取物与来自噬菌体f2的RNA一起使用时，一种因子能使蛋白质合成从温度依赖性停滞中恢复。对停滞合成中的底物和恢复反应产物的分析表明，该因子在外壳蛋白终止水平起作用，并且它也影响非外壳蛋白产物的合成。该恢复因子不同于释放因子RF-1、RF-2和RF-3。先前用于研究释放的模型系统未能对蛋白质链终止中的至少一种重要功能进行评分。
