School of Life Sciences, Södertörn University, SE-141 89 Huddinge, Sweden.
Genome Biol. 2011 Jul 19;12(7):R65. doi: 10.1186/gb-2011-12-7-r65.
Understanding the adaptive changes that alter the function of proteins during evolution is an important question for biology and medicine. The increasing number of completely sequenced genomes from closely related organisms, as well as individuals within species, facilitates systematic detection of recent selection events by means of comparative genomics.
We have used genome-wide strain-specific single nucleotide polymorphism data from 64 strains of budding yeast (Saccharomyces cerevisiae or Saccharomyces paradoxus) to determine whether adaptive positive selection is correlated with protein regions showing propensity for different classes of structure conformation. Data from phylogenetic and population genetic analysis of 3,746 gene alignments consistently shows a significantly higher degree of positive Darwinian selection in intrinsically disordered regions of proteins compared to regions of alpha helix, beta sheet or tertiary structure. Evidence of positive selection is significantly enriched in classes of proteins whose functions and molecular mechanisms can be coupled to adaptive processes and these classes tend to have a higher average content of intrinsically unstructured protein regions.
We suggest that intrinsically disordered protein regions may be important for the production and maintenance of genetic variation with adaptive potential and that they may thus be of central significance for the evolvability of the organism or cell in which they occur.
理解在进化过程中改变蛋白质功能的适应性变化，是生物学和医学的一个重要问题。越来越多的来自密切相关生物的完全测序基因组，以及物种内的个体，通过比较基因组学，有助于系统地检测到最近的选择事件。
我们利用来自 64 株 budding yeast（酿酒酵母或 paradoxus 酿酒酵母）的全基因组菌株特异性单核苷酸多态性数据，确定适应性正选择是否与表现出不同结构构象类倾向的蛋白质区域有关。对 3746 个基因比对的系统发育和群体遗传学分析的数据一致表明，与α螺旋、β片层或三级结构区域相比，蛋白质中无规卷曲区域的正达尔文选择程度显著更高。正选择的证据在功能和分子机制可以与适应性过程相关联的蛋白质类别中明显富集，这些类别往往具有更高的无规卷曲蛋白质区域的平均含量。
我们认为无规卷曲的蛋白质区域可能对具有适应性潜力的遗传变异的产生和维持很重要，因此它们可能对发生它们的生物体或细胞的可进化性具有核心意义。
