减少氨基酸替代矩阵在现代蛋白质中发现古代编码字母的痕迹
Jordan Douglas1,2, Remco Bouckaert2,3, Charles W Carter4
1Department of Physics, The University of Auckland, Auckland, New Zealand.
Molecular biology and evolution
|August 12, 2025
概括
生命早期使用的氨基酸较少,挑战了当前的进化模型. 考虑到氨基酸字母的变化,新的模型为蛋白质进化和遗传密码的起源提供了更准确的时间表.
科学领域:
- 进化生物学是进化的生物学.
- 分子生物学分子生物学
- 生物化学 生化学
背景情况:
- 所有生命都使用20种正规的氨基酸,但早期系统可能更少.
- 现有的进化模型假设一个恒定的氨基酸字母表,不适合像氨基酸-tRNA合成酶 (aaRS) 这样的酶.
研究的目的:
- 开发新的进化模型,将编码字母大小随时间变化的变化纳入其中.
- 为了测试一个从19个氨基酸过渡到20个氨基酸的假设.
主要方法:
- 创建了一个类替代模型,考虑编码字母大小的进化变化.
- 采用贝叶斯系遗传学框架来改进系遗传学估计.
- 使用蛋白质数据集测试了一个双字母假设.
主要成果:
- 对于年轻的真核蛋白质,双字母假设被拒绝,但对于在最后一个普遍共同祖先之前的古老蛋白质,则得到了支持.
- 标准方法高估了来自减少编码字母表的蛋白质的分歧年龄.
- 新模型将蛋白质进化时间线与地球历史更紧密地对齐.
结论:
- 氨基酸-tRNA合成酶 (aaRS) 功能分支事件可能推动了遗传代码的进化.
- 未知的进化力量也为遗传密码的发展做出了贡献.
- 该研究为古代蛋白质遗传学提供了一个框架,并对早期分子生物学提供了洞察力.
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