Yang Haiwang, Wu Ying, Feng Jing, Yang Sihai, Tian Dacheng
State Key Laboratory of Pharmaceutical Biotechnology, Department of Biology, Nanjing University, Nanjing 210093, China.
Genomics. 2009 Jan;93(1):90-7. doi: 10.1016/j.ygeno.2008.09.009. Epub 2008 Nov 4.
Mutations, which can alter amino acid constitution, contribute greatly to protein evolution. However, little is reported of their pattern during protein structural evolution. We investigated the distribution of non-synonymous single nucleotide polymorphisms (nsSNPs) and insertions/deletions (indels) along mammal and fruit fly proteins. We found the nsSNPs (and d(N)) and indels increased in protein boundary regions, and this pattern is inversely correlated with the distribution of protein domain density. Additionally, synonymous substitutions (and d(S)) are reduced in 5' and 3' regions, indicating more variable protein boundaries, compared with central interior. All evidence suggests that the inner part of coding sequences (CDSs) is comparatively conserved, whereas the 5' and 3' regions, with higher evolution rates, are more variable. We assumed that due to greater frequencies of nsSNPs and indels in adaptive regions of CDSs it could be easier to ultimately alter, gain, or lose amino acids, thus becoming the front line of protein evolution.
能够改变氨基酸组成的突变对蛋白质进化有很大贡献。然而，关于它们在蛋白质结构进化过程中的模式却鲜有报道。我们研究了哺乳动物和果蝇蛋白质中非同义单核苷酸多态性（nsSNPs）和插入/缺失（indels）的分布情况。我们发现，nsSNPs（以及d(N)）和indels在蛋白质边界区域增加，且这种模式与蛋白质结构域密度的分布呈负相关。此外，同义替换（以及d(S)）在5'和3'区域减少，这表明与中央内部相比，蛋白质边界更具变异性。所有证据表明，编码序列（CDSs）的内部部分相对保守，而进化速率较高的5'和3'区域则更具变异性。我们推测，由于CDSs适应区域中nsSNPs和indels的频率更高，最终改变、添加或缺失氨基酸可能更容易，因此成为蛋白质进化的前沿。
