Randerath E, Gupta R C, Morris H P, Randerath K
Biochemistry. 1980 Jul 22;19(15):3476-83. doi: 10.1021/bi00556a011.
The nucleotide sequences of two major tRNALeu species (anticodon Mn-A-A)isolated from Morris hepatoma 5123D were determined by a combination of a newly developed thin-layer readout sequencing method [Gupta, R. C., & Randerath, K. (1979) Nucleic Acids Res. 6, 3443-3458] and additional 3H- and 32P-labeled derivative methods entailing chromatographic fingerprinting and base-specific enzymatic cleavages. The nucleotide sequence of the two hepatoma tRNAMm-A-ALeu species, one of which has U and the other of which has A in position 50 at the tip of the long extra arm, is pG-U-C-A-G-m2G-A-U-G-(m2)G-C-(ac4)C-G-A-G-U-G-G-D-C-psi-A-A-G-G-C-m22G-C-C-A-G-A--C-U-Mm-A-A-m1G*-psi-psi-C-U-G-G-L-(psi)U-C-C-G-U- or A-A-U-G-G-A-G-m5C-G-U-G-G-G-T-psi-C-G-m1A-A-U-C-C-C-A-C-U-U-C-U-G-A-C-A-C-C-AOH. These are the first leucine tRNA sequences from higher eukaryotes that have been determined. Noteworthy features of the mammalian leucine tRNAs are the presence of psi in the beta region of the D loop and the occurrence of three unknown hypermodified nucleosides (Mm, m1G*, and L) in positions 35, 38, and 45, respectively. m1G* was converted to m1G by treatment with alkali. Sequencing gels indicated that the parent base of the 2'-O-methylated nucleoside Mm may be a pyrimidine, probably a C derivative, as indicated by the chromatographic behavior of nucleotides containing Mm. The presence of a pyrimidine in the wobble position would be consistent with the antidodon sequence Mm-A-A and the leucine condons U-U-G and U-U-A. The occurrence of a hypermodified nucleoside, L, in the first position of the long extra arm appears unusual; thus far the only modified nucleoside found in this position is Um in eukaryotic serine tRNAs. Since all tRNAs with a long extra arm sequenced to date have a pyrimidine in this position, L is likely to be a pyrimidine, probably a U derivative, as inferred from chromatographic data.
从莫里斯肝癌5123D中分离出的两种主要亮氨酸tRNA（反密码子为Mm-A-A）的核苷酸序列，是通过一种新开发的薄层读出测序方法[古普塔，R.C.，& 兰德拉斯，K.（1979年）《核酸研究》6，3443 - 3458]与其他涉及色谱指纹图谱和碱基特异性酶切的3H和32P标记衍生方法相结合来确定的。两种肝癌tRNAMm-A-ALeu的核苷酸序列，其中一种在长额外臂末端的第50位有U，另一种在该位置有A，其序列为pG-U-C-A-G-m2G-A-U-G-(m2)G-C-(ac4)C-G-A-G-U-G-G-D-C-psi-A-A-G-G-C-m22G-C-C-A-G-A--C-U-Mm-A-A-m1G*-psi-psi-C-U-G-G-L-(psi)U-C-C-G-U-或A-A-U-G-G-A-G-m5C-G-U-G-G-G-T-psi-C-G-m1A-A-U-C-C-C-A-C-U-U-C-U-G-A-C-A-C-C-AOH。这些是已确定的来自高等真核生物的首批亮氨酸tRNA序列。哺乳动物亮氨酸tRNA的显著特征是在D环的β区域存在假尿苷（psi），以及分别在第35、38和45位出现三种未知的高度修饰核苷（Mm、m1G和L）。用碱处理后，m1G转变为m1G。测序凝胶表明，2'-O-甲基化核苷Mm的母碱基可能是嘧啶，可能是C的衍生物，含Mm的核苷酸的色谱行为表明了这一点。摆动位置存在嘧啶与反密码子序列Mm-A-A以及亮氨酸密码子U-U-G和U-U-A是一致的。在长额外臂的第一位出现高度修饰核苷L似乎不寻常；迄今为止，在这个位置发现的唯一修饰核苷是真核丝氨酸tRNA中的Um。由于迄今为止测序的所有具有长额外臂的tRNA在这个位置都有一个嘧啶，根据色谱数据推断，L可能是嘧啶，可能是U的衍生物。
