Article

Amino acid biogenesis, evolution of the genetic code and aminoacyl-tRNA synthetases.

Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel.
Journal of Theoretical Biology (impact factor: 2.21). 07/2004; 228(3):389-96. DOI:10.1016/j.jtbi.2004.01.014 pp.389-96
Source: PubMed

ABSTRACT The aminoacyl-tRNA synthetases (aaRSs) ensure the fidelity of the translation of the genetic code, covalently attaching appropriate amino acids to the corresponding nucleic acid adaptor molecules-tRNA. The fundamental role of aminoacylation reaction catalysed by aaRSs implies that representatives of the family are thought to be among the earliest proteins to appear. Based on sequence analysis and catalytic domain structure, aaRSs have been partitioned into two classes of 10 enzymes each. However, based on the structural and sequence data only, it will not be easily understood that the present partitioning is not governed by chance. Our findings suggest that organization of amino acid biosynthetic pathways and clustering of aaRSs into different classes are intimately related to one another. A plausible explanation for such a relationship is dictated by early link between aaRSs and amino acids biosynthetic proteins. The aaRSs catalytic cores are highly relevant to the ancient metabolic reactions, namely, amino acids and cofactors biosynthesis. In particular we show that class II aaRSs mostly associated with the primordial amino acids, while class I aaRSs are usually related to amino acids evolved lately. Reasoning from this we propose a possible chronology of genetic code evolution.

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Keywords

aaRSs catalytic cores
 
amino acid biosynthetic pathways
 
amino acids
 
amino acids biosynthetic proteins
 
aminoacyl-tRNA synthetases
 
aminoacylation reaction catalysed
 
ancient metabolic reactions
 
appropriate amino acids
 
catalytic domain structure
 
class II aaRSs
 
cofactors biosynthesis
 
corresponding nucleic acid adaptor molecules-tRNA
 
earliest proteins
 
genetic code
 
genetic code evolution
 
possible chronology
 
present partitioning
 
primordial amino acids
 
representatives
 
sequence analysis
 

Liron Klipcan