EVOLUTION AND tRNA RECOGNITION OF THREONYL-tRNA SYNTHETASE FROM AN EXTREME THERMOPHILIC ARCHAEON, Aeropyrum pernix K1

Yoshiyuki Nagaoka, Kazuhide Ishikura, Atsushi Kuno, Tsunemi Hasegawa
2003 Viva Origino  
An extreme thermophilic archaeon, Aeropyrum pernix K1 possesses two possible threonyl-tRNA synthetase genes. Sequence homology analysis of these genes with other species threonyl-tRNA synthetase showed that the shorter gene did not possess motif-2 and motif-3 of catalytic core that were conserved in class II aminoacyl-tRNA synthetases. On the other hand, the longer gene had almost all amino acids that were expected to be involved in substrate binding and catalytic activity. As a striking
more » ... , it was found that the sequence of the longer threonyl-tRNA synthetase was unique in its quite compact N-terminal domain. This peculiar structure of A. pernix threonyl-tRNA synthetase may suggest one of the hints that can decipher not only the evolutionary position of this archaeon but also the evolutionary process for threonyl-tRNA synthetase. Cross-species aminoacylation experiments showed that threonyl-tRNA synthetase from A. pernix threonylated not only Escherichia coli threonine tRNA having A73 as a discriminator base, but also an extreme halophilic archaeon Haloferax volcanii threonine tRNA possessing U73. These results indicate that A. pernix threonyl-tRNA synthetase does not recognize the discriminator base like E. coli system.
doi:10.50968/vivaorigino.31.1_62 fatcat:gbjdfexau5aifnmoxowqkptnnm