Evidence that two present-day components needed for the genetic code appeared after nucleated cells separated from eubacteria

被引:37
作者
dePouplana, LR [1 ]
Frugier, M [1 ]
Quinn, CL [1 ]
Schimmel, P [1 ]
机构
[1] CUBIST PHARMACEUT INC,CAMBRIDGE,MA 02139
关键词
aminoacyl-tRNA synthetase; molecular evolution;
D O I
10.1073/pnas.93.1.166
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
The trinucleotide/amino acid relationships of the present-day genetic code are established by the amino-acylation reactions of tRNA synthetases, whereby each of 20 specific amino acids is attached to its cognate tRNAs, which bear anticodon trinucleotides, Because of its universality, the appearance of the modern genetic code is thought to predate the separation of prokaryotic and eukaryotic organisms in the universal phylogenetic tree. In the light of new sequence information, we present here a phylogenetic analysis that shows an unusual picture for tyrosyl- and tryptophanyl-tRNA synthetases. In particular, the eukaryotic tyrosyl- and tryptophanyl-tRNA synthetases are more related to each other than to their respective prokaryotic counterparts. In contrast, each of the other 18 eukaryotic synthetases is more related to its prokaryotic counterpart than to any eukaryotic synthetase specific for a different amino acid, Our results raise the possibility that present day tyrosyl- and tryptophanyl-tRNA synthetases appeared after the separation of nucleated cells from eubacteria, The results have implications for the development of the genetic code.
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页码:166 / 170
页数:5
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