Hansen P K, Wikman F, Clark B F, Hershey J W, Uffe Petersen H
Biochimie. 1986 May;68(5):697-703. doi: 10.1016/s0300-9084(86)80163-8.
It has recently been shown that the non-formylated initiator Met-tRNAfMet from E. coli can form a stable ternary complex with the elongation factor EF-Tu and GTP. Using the protection of EF-Tu:GTP against spontaneous hydrolysis of the aminoacylester bond of Met-tRNAfMet, we confirm these results, and show that the protection is specific for the non-formylated form of the initiator tRNA. The ternary complex Met-tRNAfMet:EF-Tu:GTP can be isolated by column chromatography in a way similar to that demonstrated previously with EF-Tu complexed to the elongator Met-tRNAmMet. 32P-labeled Met-tRNAfMet within the ternary complex was analyzed by the footprinting technique. The pattern of initiator tRNA protection by EF-Tu against ribonuclease digestion is not significantly different from the one found previously for elongator tRNAs. These results lead us to suggest that the initiator tRNAfMet, under growth conditions which do not permit formylation, may to some extent function as an elongator tRNA.
最近有研究表明，来自大肠杆菌的非甲酰化起始甲硫氨酰 - tRNAfMet能与延伸因子EF - Tu和GTP形成稳定的三元复合物。利用EF - Tu:GTP对甲硫氨酰 - tRNAfMet氨酰酯键自发水解的保护作用，我们证实了这些结果，并表明这种保护作用对起始tRNA的非甲酰化形式具有特异性。三元复合物甲硫氨酰 - tRNAfMet:EF - Tu:GTP可以通过柱色谱法分离，其方式类似于之前展示的EF - Tu与延伸甲硫氨酰 - tRNAmMet复合的情况。通过足迹技术分析了三元复合物中32P标记的甲硫氨酰 - tRNAfMet。EF - Tu对起始tRNA免受核糖核酸酶消化的保护模式与之前发现的延伸tRNA的模式没有显著差异。这些结果使我们认为，在不允许甲酰化的生长条件下，起始tRNAfMet可能在一定程度上发挥延伸tRNA的功能。
