Wagner R, Garrett R A
Eur J Biochem. 1979 Jul;97(2):615-21. doi: 10.1111/j.1432-1033.1979.tb13151.x.
[32P]TRNALys, from Escherichia coli, was modified with kethoxal, in the presence and absence of the oligonucleotide codon (A)4. The presence of the codon resulted in a faster modification rate of the tRNA at three guanine sites which were identified by a diagonal fingerprint method. A large increase in the modification rate occurred at the 7-methylguanosine residue 46 (m7G-46) in the presence of the codon: weakly enhanced modification was observed at G-15 and G-57. It is concluded that the formation of a codon-anticodon complex induces, primarily, a conformational change involving disruption of the m7G-46 from the m7G-46 . G-22 . C-13 base triple. Subsequently, the guanines of G-15 and G-57, in the D and T loops, respectively, become slightly more reactive, suggesting a weak tendency for these two interacting arms to unfold. The results are interpreted in terms of an equilibrium between two main conformers, and a third minor one; the possible significance of these conformers in protein biosynthesis, is considered.
来自大肠杆菌的[32P]赖氨酸转运核糖核酸（tRNALys）在有和没有寡核苷酸密码子（A）4的情况下用乙二醛进行修饰。密码子的存在导致通过对角线指纹法鉴定的三个鸟嘌呤位点处tRNA的修饰速率加快。在密码子存在的情况下，46位的7-甲基鸟苷残基（m7G-46）的修饰速率大幅增加：在G-15和G-57处观察到修饰略有增强。结论是密码子-反密码子复合物的形成主要诱导了一种构象变化，涉及m7G-46与m7G-46.G-22.C-13碱基三联体的破坏。随后，分别位于D环和T环中的G-15和G-57的鸟嘌呤变得略微更具反应性，表明这两个相互作用臂有轻微的展开倾向。结果根据两个主要构象异构体和第三个次要构象异构体之间的平衡进行解释；考虑了这些构象异构体在蛋白质生物合成中的可能意义。
