THE ANTICODON TRIPLET IS NOT SUFFICIENT TO CONFER METHIONINE ACCEPTANCE TO A TRANSFER-RNA
THE ANTICODON TRIPLET IS NOT SUFFICIENT TO CONFER METHIONINE ACCEPTANCE TO A TRANSFER-RNA
复制标题
DOI：
10.1073/pnas.89.22.10768
复制
发表时间：
1992-11-15
影响因子：
11.1
通讯作者：
FASIOLO, F
中科院分区：
文献类型：
--
作者：
SENGER, B;DESPONS, L;FASIOLO, F
先前的研究表明，仅反密码子 CAU 的存在就足以赋予 tRNA 甲硫氨酸的接受性。大肠杆菌非甲硫氨酸 tRNA 向甲硫氨酸接受物种的转化是通过替换重建整个甲硫氨酸反密码子环以及保留（或引入）接受体茎碱基 A73 来获得的。我们在此表明，当移植到酵母天冬氨酸 tRNA 中时，单独的 CAU 三联体无法赋予甲硫氨酸接受性。除了 CAU 之外，还需要酵母 tRNA(Met) 反密码子环和 A73 的两个非反密码子碱基来接受甲硫氨酸。这些非反密码子碱基在其他包含 CAU 的 tRNA 框架中的重要性也得到了证实。这些特定的非反密码子碱基相互作用对转移 RNA 的甲硫氨酸接受做出了巨大的热力学贡献。
Previous work suggested that the presence of the anticodon CAU alone was enough to confer methionine acceptance to a tRNA. Conversions of Escherichia coli nonmethionine tRNAs to a methionine-accepting species were obtained by substitutions reconstructing the whole methionine anticodon loop together with preservation (or introduction) of the acceptor stem base A73. We show here that the CAU triplet alone is unable to confer methionine acceptance when transplanted into a yeast aspartic tRNA. Both non-anticodon bases of the anticodon loop of yeast tRNA(Met) and A73 are required in addition to CAU for methionine acceptance. The importance of these non-anticodon bases in other CAU-containing tRNA frameworks was also established. These specific non-anticodon base interactions make a substantial thermodynamic contribution to the methionine acceptance of a transfer RNA.