Shpaer E G
Nucleic Acids Res. 1985 Jan 11;13(1):275-88. doi: 10.1093/nar/13.1.275.
A secondary structure model was proposed for mRNAs during translation (in a polysome) where the secondary structure is described by a set of small unbranched hairpins. Computer simulation experiments reveal that the number of hairpins is much greater (P less than 10(-6) in highly expressed mRNAs from E. coli as compared with the random sequences coding for the same amino acid sequence, i.e. certain synonymous codons are used in definite mRNA positions to increase the number of hairpins. No constraints on the amino acid sequence, which would affect the secondary structure of mRNAs, were found. The codons UGU, UGC (Cys), GCC (Ala), ACA, ACG (Thr), CCU, CCC (Pro), etc. translated by minor tRNAs were found to occur significantly more frequently in the position 5' to the hairpins than the other codons translated by major tRNAs (P less than 5.10(-6). This correlation leads to the hypothesis that the process of hairpin unfolding can increase the time of translocation from the A to P ribosome site of the codon 5' to the hairpin, thus decreasing the probability of translational error (the latter would likely occur more frequently in the codons translated by minor tRNAs).
提出了一种翻译过程中（在多核糖体中）mRNA的二级结构模型，其中二级结构由一组小的无分支发夹描述。计算机模拟实验表明，与编码相同氨基酸序列的随机序列相比，大肠杆菌中高表达mRNA的发夹数量要多得多（P小于10^(-6)），即特定的同义密码子在特定的mRNA位置被使用以增加发夹数量。未发现对影响mRNA二级结构的氨基酸序列有任何限制。发现由次要tRNA翻译的密码子UGU、UGC（半胱氨酸）、GCC（丙氨酸）、ACA、ACG（苏氨酸）、CCU、CCC（脯氨酸）等，在发夹5'端位置出现的频率明显高于由主要tRNA翻译的其他密码子（P小于5×10^(-6)）。这种相关性导致了一个假设，即发夹展开过程可以增加密码子从核糖体A位点到5'端发夹的P位点转位的时间，从而降低翻译错误的概率（后者可能在由次要tRNA翻译的密码子中更频繁地发生）。
