EVOLUTION OF THE MITOCHONDRIAL GENETIC-CODE .1. ORIGIN OF AGR SERINE AND STOP CODONS IN METAZOAN MITOCHONDRIA
EVOLUTION OF THE MITOCHONDRIAL GENETIC-CODE .1. ORIGIN OF AGR SERINE AND STOP CODONS IN METAZOAN MITOCHONDRIA
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DOI：
10.1007/bf02100203
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发表时间：
1989-01-01
影响因子：
3.9
通讯作者：
WATANABE, K
中科院分区：
文献类型：
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作者：
OSAWA, S;OHAMA, T;WATANABE, K
AGA和AGG（AGR）是通用遗传密码中的精氨酸密码子。这些密码子被读为丝氨酸，或用作后生动物的终止密码子。由AGR编码的精氨酸残基在酵母菌或锥虫瘤中用精氨酸CGN编码整个Metazoan线粒体。 Metazoan线粒体中的AGR丝氨酸位点主要占据酵母中的相应部位，或者通过UCN丝氨酸，AGY丝氨酸或甲锥虫的锥虫线粒体在相应的位置中，除非丝氨酸或精氨酸氨基氨基酸或氨基酸。基于这些观察结果，我们提出了以下进化事件。由于删除了tRNA arg（UCU）和通过转换为cgn精氨酸冷凝器消除AGR密码子，AGR密码子变得未分配。通过丝氨酸tRNA与AGR密码子的配对能力获取后，除精氨酸突变为AGR以外的其他氨基酸的密码子，并在丝氨酸TRNA中通过contyodongcu捕获。在脊椎动物线粒体进化过程中，AGR终止密码子可能是通过删除第一个核苷酸U的uag停止创建的，并通过使用R作为祖先UAG停止旁边存在的第三个核苷酸。
AGA and AGG (AGR) are arginine codons in the universal genetic code. These codons are read as serine or are used as stop codons in metazoan mitochondria. The arginine residues coded by AGR in yeast or Trypanosoma are coded by arginine CGN throughout metazoan mitochondria. AGR serine sites in metazoan mitochondria are occupied mainly in corresponding sites in yeast or Trypanosoma mitochondria by UCN serine, AGY serine, or codons for amino acids other than serine or arginine. Based on these observations, we propose the following evolutionary events. AGR codons became unassigned because of deletion of tRNA Arg (UCU) and elimination of AGR codons by conversion to CGN arginine condons. Upon acquisition by serine tRNA of pairing ability with AGR codons, some codons for amino acids other than arginine mutated to AGR, and were captured by anticodon GCU in serine tRNA. During vertebrate mitochondrial evolution, AGR stop codons presumably were created from UAG stop by deletion of the first nucleotide U and by use of R as the third nucleotide that had existed next to the ancestral UAG stop.