Licznar Patricia, Mejlhede Nina, Prère Marie-Françoise, Wills Norma, Gesteland Raymond F, Atkins John F, Fayet Olivier
Microbiologie et Génétique Moléculaire, CNRS, 118 route de Narbonne, 31062 Toulouse Cedex, France.
EMBO J. 2003 Sep 15;22(18):4770-8. doi: 10.1093/emboj/cdg465.
Programmed -1 ribosomal frameshifting, involving tRNA re-pairing from an AAG codon to an AAA codon, has been reported to occur at the sequences CGA AAG and CAA AAG. In this study, using the recoding region of insertion sequence IS3, we have investigated the influence on frameshifting in Escherichia coli of the first codon of this type of motif by changing it to all other NNA codons. Two classes of NNA codons were distinguished, depending on whether they favor or limit frameshifting. Their degree of shiftiness is correlated with wobble propensity, and base 34 modification, of their decoding tRNAs. A more flexible anticodon loop very likely makes the tRNAs with extended wobble more prone to liberate the third codon base, A, for re-pairing of tRNALys in the -1 frame.
据报道，程序性-1核糖体移码涉及tRNA从AAG密码子重新配对到AAA密码子，发生在序列CGA AAG和CAA AAG处。在本研究中，我们利用插入序列IS3的重编码区域，通过将这类基序的第一个密码子替换为所有其他NNA密码子，研究了其对大肠杆菌中移码的影响。根据它们对移码的促进或限制作用，区分出两类NNA密码子。它们的移码程度与解码tRNA的摆动倾向和第34位碱基修饰相关。一个更灵活的反密码子环很可能使具有扩展摆动的tRNA更容易释放第三个密码子碱基A，以便在-1框架中与赖氨酸tRNA重新配对。
