Decoding of tandem quadruplets by adjacent tRNAs with eight-base anticodon loops
Decoding of tandem quadruplets by adjacent tRNAs with eight-base anticodon loops
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DOI：
10.1093/nar/28.18.3615
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发表时间：
2000-09-15
影响因子：
14.9
通讯作者：
Atkins, JF
中科院分区：
文献类型：
--
作者：
Moore, B;Nelson, CC;Atkins, JF
为了扩展用于多种非天然氨基酸的特异性的遗传密码，需要这些新氨基酸的独特密码子。作为研究四联体作为密码子的潜力的一部分，已经研究了通过具有八个碱基的反密码子环的工程化tRNA（Leu）对串联UAGA四联体的解码。当GCC是紧挨着第一个UAGA四联体的5'的密码子，并且释放因子I部分失活时，串联UAGA以至少10%的总效率指定两个亮氨酸。在tRNA的反密码子环位置32处存在嘌呤，其解码第一个UAGA的5'密码子，似乎影响随后密码子的翻译。另一个发现是反密码子从密码子的核糖体内解离以及它们在重叠或附近密码子处与mRNA的重新配对。在GCC被CGG取代的一种情况下，当恢复解码时，在重新配对时仅可以形成单个沃森-克里克碱基对。这对某些程序性移码的机制有影响。
To expand the genetic code for specification of multiple non-natural amino acids, unique codons for these novel amino acids are needed. As part of a study of the potential of quadruplets as codons, the decoding of tandem UAGA quadruplets by an engineered tRNA(Leu) with an eight-base anticodon loop, has been investigated. When GCC is the codon immediately 5' of the first UAGA quadruplet, and release factor I is partially inactivated, the tandem UAGAs specify two leucines with an overall efficiency of at least 10%. The presence of a purine at anticodon loop position 32 of the tRNA decoding the codon 5' to the first UAGA seems to influence translation of the following codon. Another finding is intraribosomal dissociation of anticodons from codons and their re-pairing to mRNA at overlapping or nearby codons, In one case where GCC is replaced by CGG, only a single Watson-Crick base pair can form upon re-pairing when decoding is resumed. This has implications for the mechanism of some cases of programmed frameshifting.