Kinetic parameters for tyrosylation of wild-type tRNATyr molecules or variants by TyrRSapm and methionylation of wild-type tRNAMet molecules or variants by MetRSapm

Range Table - link
Organism Acanthamoeba polyphaga Mimivirus
Reference Abergel C, Rudinger-Thirion J, Giegé R, Claverie JM. Virus-encoded aminoacyl-tRNA synthetases: structural and functional characterization of mimivirus TyrRS and MetRS. J Virol. 2007 Nov81(22):12406-17. p.12409 table 2PubMed ID17855524
Method P.12407 left column 2nd paragraph:"This article reports a detailed functional study of two of the four viral class I aaRS, A. polyphaga mimivirus TyrRS (TyrRSapm) and A. polyphaga mimivirus MetRS (MetRSapm), and the structural study of TyrRSapm in complex with tyrosinol. These enzymes were found to exhibit the specificity and function predicted from their sequences, but the three-dimensional structure of TyrRSapm exhibited significant differences from its cellular counterparts."
Comments P.12413 left column 3rd paragraph:"Methionylation properties of MetRSapm.Wild-type native initiator tRNAMets from E. coli and S. cerevisiae were tested for methionylation by MetRSapm. Both substrates were aminoacylated with kinetic parameters (Km and kcat) slightly decreased for the eukaryal tRNA, which resulted in a twofold loss in methionylation efficiency compared to that of the E. coli tRNAMet (Table 2). Unmodified yeast tRNAMet transcript behaves globally as its native counterpart, with only a twofold loss in aminoacylation efficiency. Noticeable, however, are the low Km and high kcat values of yeast tRNAMet transcript towards MetRSapm compared to the values determined with the yeast enzyme. Replacing individually the anticodon residues abolishes methionine acceptance (Table 2), as has already been demonstrated for E. coli and yeast MetRSs (refs 52, 53). Thus, as for all MetRS, the C34U35A36 anticodon residues govern specific recognition of tRNAMet by MetRSapm." See notes beneath table. aaRS=aminoacyl-tRNA synthetases
Entered by Uri M
ID 112378