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首页> 外文期刊>Astrobiology >Did Evolution Select a Nonrandom 'Alphabet' of Amino Acids?
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Did Evolution Select a Nonrandom 'Alphabet' of Amino Acids?

机译：Evolution是否选择了氨基酸的非随机“字母”？

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摘要

The last universal common ancestor of contemporary biology (LUCA) used a precise set of 20 amino acids as a standard alphabet with which to build genetically encoded protein polymers. Considerable evidence indicates that some of these amino acids were present through nonbiological syntheses prior to the origin of life, while the rest evolved as inventions of early metabolism. However, the same evidence indicates that many alternatives were also available, which highlights the question: what factors led biological evolution on our planet to define its standard alphabet? One possibility is that natural selection favored a set of amino acids that exhibits clear, nonrandom properties—a set of especially useful building blocks. However, previous analysis that tested whether the standard alphabet comprises amino acids with unusually high variance in size, charge, and hydrophobicity (properties that govern what protein structures and functions can be constructed) failed to clearly distinguish evolution's choice from a sample of randomly chosen alternatives. Here, we demonstrate unambiguous support for a refined hypothesis: that an optimal set of amino acids would spread evenly across a broad range of values for each fundamental property. Specifically, we show that the standard set of 20 amino acids represents the possible spectra of size, charge, and hydrophobicity more broadly and more evenly than can be explained by chance alone. Key Words: Astrobiology—Evolution—Molecular biology—Modeling studies.
机译：当代生物学的最后一位通用祖先（LUCA）使用一组精确的20个氨基酸作为标准字母，用于构建遗传编码的蛋白质聚合物。大量证据表明，其中一些氨基酸是在生命起源之前通过非生物合成存在的，而其余则是早期代谢的发明。但是，同样的证据表明，还有许多替代方法可用，这突出了一个问题：哪些因素导致了我们星球上的生物进化来定义其标准字母？一种可能是自然选择偏爱一组显示清晰，非随机性质的氨基酸-一组特别有用的结构单元。但是，先前的测试测试标准字母是否包含大小，电荷和疏水性差异非常大的氨基酸（决定可以构建哪些蛋白质结构和功能的特性），这一分析未能从随机选择的替代品中清楚地区分进化的选择。在这里，我们证明了对精确假设的明确支持：一组最佳氨基酸将均匀分布在每个基本属性的广泛值范围内。具体而言，我们显示了由20个氨基酸组成的标准组，比仅由偶然的机会所解释的范围更广，更均匀地代表了大小，电荷和疏水性的可能光谱。关键词：天体生物学—进化—分子生物学—建模研究。

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  • 来源
    《Astrobiology》 |2011年第3期|p.235-240|共6页
  • 作者

    Gayle K. Philip; Stephen J. Freeland;

  • 作者单位

    NASA Astrobiology Institute, University of Hawaii, Honolulu, Hawaii;

    NASA Astrobiology Institute, University of Hawaii, Honolulu, Hawaii;

  • 收录信息 美国《科学引文索引》(SCI);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
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