Inagaki Y, Kojima A, Bessho Y, Hori H, Ohama T, Osawa S
Department of Biology School of Science, Nagoya University, Japan.
J Mol Biol. 1995 Aug 25;251(4):486-92. doi: 10.1006/jmbi.1995.0450.
In Myocoplasma capricolum, codon family boxes except for arginine and threonine (CUN leucine, GUN valine, UCN serine, CCN proline, GCN alanine, and GGN glycine) have only a single tRNA species with the anticodon sequence UNN (N is U, C, A or G), the first nucleoside U being unmodified. Incorporation of the [3H]amino acid into the peptide fraction was examined with the M. capricolum cell-free translation system. Synthetic mRNA containing each of the respective amino acid codons in the coding frame was subjected to translation. The tRNAUNN translated all the family box codons with similar, if not equal, efficiencies. In M. capricolum, there are two species of threonine tRNA, tRNA(UGUThr) and tRNA(AGUThr), the first nucleoside U or A being unmodified. The tRNA(UGUThr) species translates codons ACA, ACG and ACU efficiently, and ACC only poorly. In contrast, the tRNA(AGUThr) species translates codons ACU, ACC and ACG efficiently and ACA poorly.
在山羊支原体中，除精氨酸和苏氨酸的密码子家族框（CUN亮氨酸、GUN缬氨酸、UCN丝氨酸、CCN脯氨酸、GCN丙氨酸和GGN甘氨酸）外，只有一种带有反密码子序列UNN（N为U、C、A或G）的tRNA，第一个核苷U未被修饰。使用山羊支原体无细胞翻译系统检测了[3H]氨基酸掺入肽段的情况。对编码框中包含各个氨基酸密码子的合成mRNA进行翻译。tRNAUNN以相似（即使不相等）的效率翻译所有家族框密码子。在山羊支原体中，有两种苏氨酸tRNA，即tRNA(UGUThr)和tRNA(AGUThr)，第一个核苷U或A未被修饰。tRNA(UGUThr)能高效翻译密码子ACA、ACG和ACU，而对ACC的翻译效率很低。相反，tRNA(AGUThr)能高效翻译密码子ACU、ACC和ACG，而对ACA的翻译效率很低。
