Genetic analysis of the E site during RF2 programmed frameshifting
Genetic analysis of the E site during RF2 programmed frameshifting
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DOI：
10.1261/rna.638707
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发表时间：
2007-09-01
期刊：
影响因子：
4.5
通讯作者：
Curran, James F.
中科院分区：
文献类型：
--
作者：
Sanders, Christina L.;Curran, James F.
核糖体E位点的作用尚未完全了解。先前的证据表明，E位点的脱酰基tRNA可以防止移码。我们假设，如果E位点密码子必须与其tRNA分离才能进行移码，那么弱密码子：反密码子双链体应该比强双链体允许更大的移码。使用充分表征的大肠杆菌RF2（prfB）程序移码研究移码，我们诱变的E-位点三联体的所有Unn和Cnn密码子。这些变体应代表非常宽范围的双链体稳定性。使用两种不同的方法估计双链体稳定性。移码与稳定性呈负相关，这两种方法都是如此。这些发现表明脱酰基tRNA和E位点密码子之间的配对反对移码。我们讨论了这些研究结果的框架维护和RF2编程移码机制的影响。
The roles of the ribosomal E site are not fully understood. Prior evidence suggests that deacyl-tRNA in the E site can prevent frameshifting. We hypothesized that if the E-site codon must dissociate from its tRNA to allow for frameshifting, then weak codon: anticodon duplexes should allow for greater frameshifting than stronger duplexes. Using the well-characterized Escherichia coli RF2 ( prfB) programmed frameshift to study frameshifting, we mutagenized the E-site triplet to all Unn and Cnn codons. Those variants should represent a very wide range of duplex stability. Duplex stability was estimated using two different methods. Frameshifting is inversely correlated with stability, as estimated by either method. These findings indicate that pairing between the deacyl-tRNA and the E-site codon opposes frameshifting. We discuss the implications of these findings on frame maintenance and on the RF2 programmed frameshift mechanism.