Kuchino Y, Hanyu N, Tashiro F, Nishimura S
Proc Natl Acad Sci U S A. 1985 Jul;82(14):4758-62. doi: 10.1073/pnas.82.14.4758.
Nucleotide sequence analysis of one of several tRNA genes cloned from Tetrahymena thermophila macronuclear DNA indicated that it corresponds to a tRNA species having TTA as anticodon. Subsequently, the tRNA species corresponding to that gene was isolated and its nucleotide sequence was determined by post-labeling techniques. The nucleotide sequence was found to be pG-G-U-U-C-C-A-U-A-m2G-U-A-psi-A-G-D-G-G-D- D-A-G-U-A-C-U-G-G-G-G-A-Cm-U-Um-U-A-i6A-A-psi-C-C-C-U-U-G-A-C- m5C-U-G-G-G-U-psi-C-G-m1A-A-U-C-C-C-A-G-U-G-G-G-A-C-C-U-C-C-AOH. This tRNA sequence exactly matched the DNA sequence of the corresponding tRNA gene. The first position of anticodon is 2'-O-methyluridine (Um), forming UmUA as the anticodon, which presumably recognizes the ochre termination codon UAA. This tRNA species is aminoacylated with glutamine by a Tetrahymena crude aminoacyl tRNA synthetase fraction, suggesting that ochre termination codon is used as a glutamine codon during cytoplasmic protein synthesis in Tetrahymena.
对从嗜热四膜虫大核DNA中克隆的几个tRNA基因之一进行核苷酸序列分析表明，它对应于一种反密码子为TTA的tRNA种类。随后，分离出了与该基因对应的tRNA种类，并通过后标记技术确定了其核苷酸序列。发现该核苷酸序列为pG-G-U-U-C-C-A-U-A-m2G-U-A-ψ-A-G-D-G-G-D-D-A-G-U-A-C-U-G-G-G-G-A-Cm-U-Um-U-A-i6A-A-ψ-C-C-C-U-U-G-A-C-m5C-U-G-G-G-U-ψ-C-G-m1A-A-U-C-C-C-A-G-U-G-G-G-A-C-C-U-C-C-AOH。该tRNA序列与相应tRNA基因的DNA序列完全匹配。反密码子的第一位是2'-O-甲基尿苷（Um），形成UmUA作为反密码子，推测它识别赭石终止密码子UAA。该tRNA种类被嗜热四膜虫粗氨酰tRNA合成酶组分用谷氨酰胺进行氨酰化，这表明在嗜热四膜虫的细胞质蛋白质合成过程中，赭石终止密码子被用作谷氨酰胺密码子。
