Molecular mechanism of lysidine synthesis that determines tRNA identity and codon recognition
Molecular mechanism of lysidine synthesis that determines tRNA identity and codon recognition
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DOI：
10.1016/j.molcel.2005.06.007
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发表时间：
2005-07-22
期刊：
影响因子：
16
通讯作者：
Suzuki, T
中科院分区：
文献类型：
--
作者：
Ikeuchi, Y;Soma, A;Suzuki, T
赖氨酸(2-lysyl cytidine)是一种含有赖氨酸的胞苷衍生物，通常发现于细菌AUA密码子特异性tRNAIle的摆动位置。这种修饰决定了tRNA(IIe)的密码子和氨基酸的特异性。我们以前发现了合成赖氨酸的tRNA(IIe)-赖氨酸合成酶(His)，它利用三磷酸腺苷和赖氨酸作为底物。在这里，我们证明了赖氨酸的合成由两个连续的反应组成，这两个反应涉及腺化的tRNA中间体。突变研究表明，大肠杆菌TILs通过识别反密码子环、反密码子茎和受体茎来区分tRNA(IIe)和具有相同反密码子环的结构相似的tRNAMet。TIL结合到受体茎的反密码子区域和3‘端，覆盖了识别位点。这些发现揭示了tRNAIIe中嵌入的一种专用机制，该机制控制TIL对tRNAIIe的识别和识别，并表明该酶在正确破译遗传信息方面的重要性。
Lysidine (2-lysyl cytidine) is a lysine-containing cytidine derivative commonly found at the wobble position of bacterial AUA codon-specific tRNAIle. This modification determines both codon and amino acid specificities of tRNA(IIe). We previously identified tRNA(IIe)-lySidine synthetase (HIS) that synthesizes lysidine, for which it utilizes ATP and lysine as substrates. Here, we show that lysidine synthesis consists of two consecutive reactions that involve an adenylated tRNA intermediate. A mutation study revealed that Escherichia coli TilS discriminates tRNA(IIe) from the structurally similar tRNAMet having the same anticodon loop by recognizing the anticodon loop, the anticodon stem, and the acceptor stem. TilS was shown to bind to the anticodon region and 3' side of the acceptor stem, which cover the recognition sites. These findings reveal a dedicated mechanism embedded in tRNAIIe that controls its recognition and discrimination by TilS, and indicate the significance of this enzyme in the proper deciphering of genetic information.