Berger S, Maier V, Zawadil C, Pfeiffer E F, Bounias M
Department of Internal Medicine, University of Ulm, Germany.
Horm Metab Res. 1996 Oct;28(10):535-40. doi: 10.1055/s-2007-979847.
Similar conserved structures appear in apparently unrelated protein families. Thus, the superfamily of insulin shows an evolutionary relationship with the alpha-conotoxins of marine fish-hunting snails as indicated by methods of protein comparison. In order to reach statistical significance, the A-chains of different insulins, insulin-like growth factors, relaxins, insulin related peptides from invertebrates were drawn for comparison. These data were correlated with sequences from randomly chosen proteins. The alpha-conotoxins show identity scores up to 37.5% and similarity up to 56.2% toward the members of the insulin-superfamily. These scores conform to values achieved by comparing the relaxin and the insulin/IGF-sequences. The data show clearly that the identity and similarity values obtained in the comparison with the insulins are significantly higher than the scores of randomly chosen protein primary structures. According to our calculated data, this hormone system regulating metabolism and growth in vertebrates and the mentioned toxin-receptor system share the same evolutionary ancestor. However, this statistical approach has to be substantiated on gene level.
类似的保守结构出现在明显不相关的蛋白质家族中。因此，通过蛋白质比较方法表明，胰岛素超家族与捕食海洋鱼类的蜗牛的α-芋螺毒素存在进化关系。为了达到统计学显著性，绘制了不同胰岛素、胰岛素样生长因子、松弛素、来自无脊椎动物的胰岛素相关肽的A链进行比较。这些数据与随机选择的蛋白质序列相关。α-芋螺毒素与胰岛素超家族成员的同一性得分高达37.5%，相似性高达56.2%。这些得分与比较松弛素和胰岛素/胰岛素样生长因子序列所获得的值一致。数据清楚地表明，与胰岛素比较获得的同一性和相似性值明显高于随机选择的蛋白质一级结构的得分。根据我们计算的数据，这种调节脊椎动物新陈代谢和生长的激素系统与上述毒素-受体系统有着共同的进化祖先。然而，这种统计方法必须在基因水平上得到证实。
