同义密码子的反常蛋白质二级结构偏好性

Abnormal Preference of Synonymous Codons for Protein Secondary Structural Types

统计分析了 119种人蛋白质和 92种大肠杆菌蛋白质的mRNA序列和蛋白质二级结构的关系 .从二肽频数出发 ,研究了同义密码子使用对蛋白质二级结构的影响 ,证明其影响在 10 %到 2 0 %的量级 .对于人和大肠杆菌 ,在 90 %置信水平上 ,4 0 0对二肽中分别有 79对和 6 0对 ,在 95 %置信水平上 ,分别有 4 5对和 36对二肽的相应密码子二联体具有不同于氨基酸的反常二级结构偏好性 。

The relationship between 119 human and 92 E.coli mRNA sequences and protein secondary structures were investigated through statistical analyses. Based on di peptide frequencies, the influences of codon usage on protein secondary structure were studied. It was demonstrated that the structure preferences of codons in 79 (or 45) di peptides were different from those of amino acid pairs for human, and they could not be explained by stochastic fluctuations at 90% (or 95%) confidence level. The corresponding number of di peptides is 60 (or 36) for E.coli at 90% (or 95%) confidence level. This means that the codon usage influences protein secondary structure at the level of 10% to 20 % in total for different species, from higher mammals to prokaryotes.