Evolution of amino acid frequencies in proteins over deep time: Inferred order of introduction of amino acids into the genetic code
Evolution of amino acid frequencies in proteins over deep time: Inferred order of introduction of amino acids into the genetic code
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DOI：
10.1093/oxfordjournals.molbev.a003988
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发表时间：
2002-10-01
影响因子：
10.7
通讯作者：
Singh, M
中科院分区：
文献类型：
--
作者：
Brooks, DJ;Fresco, JR;Singh, M
为了更全面地了解蛋白质的氨基酸组成在进化过程中是如何变化的，人们开发了一种方法来估计祖先基因组中蛋白质的组成。估计是基于后代序列中保守残基的组成和各种氨基酸保守的相对概率的经验知识。模拟用于建模和校正估计中的误差。该方法被用来推断一个大的蛋白质组的氨基酸组成的最后普遍的祖先（LUA）的所有现存物种。相对于现代蛋白质组，发现LUA蛋白质通常富含那些被认为在益生元环境中最丰富的氨基酸，而那些被认为不可用或稀缺的氨基酸则较贫乏。有人提出，推测的氨基酸组成的蛋白质在LUA可能反映了历史事件的遗传密码的建立。
To understand more fully how amino acid composition of proteins has changed over the course of evolution, a method has been developed for estimating the composition of proteins in an ancestral genome. Estimates are based upon the composition of conserved residues in descendant sequences and empirical knowledge of the relative probability of conservation of various amino acids. Simulations are used to model and correct for errors in the estimates. The method was used to infer the amino acid composition of a large protein set in the Last Universal Ancestor (LUA) of all extant species. Relative to the modern protein set, LUA proteins were found to be generally richer in those amino acids that are believed to have been most abundant in the prebiotic environment and poorer in those amino acids that are believed to have been unavailable or scarce. It is proposed that the inferred amino acid composition of proteins in the LUA probably reflects historical events in the establishment of the genetic code.