Recognition by Tryptophanyl-tRNA Synthetases of Discriminator Base on tRNATrp from Three Biological Domains

Selective incorporation of 5-hydroxytryptophan into proteins in mammalian cells

“…One approach to the generation of orthogonal tRNA-synthetase pairs takes advantage of interspecies differences in tRNA recognition elements (19). For example, Xue and coworkers (20) have shown that B. subtilis tRNA Trp is not a substrate for the tryptophantRNA synthetases from yeast and mammalian cells (21). Thus B. subtilis tRNA Trp is a likely candidate for an orthogonal suppressor tRNA in mammalian cells.…”

Dual targeting of a single tRNA Trp requires two different tryptophanyl-tRNA synthetases in Trypanosoma brucei

“…Whereas the anticodon is a phylogenetically shared identity element, the discriminator nucleotide differs between bacteria and eukaryotes (6), which explains why the two TrpRSs cannot efficiently cross-aminoacylate the corresponding tRNA Trp species (24,25). Most mitochondria decode UGA as tryptophan, thus it is clear that the bacterial-type mitochondrial TrpRS has evolved to tolerate an UCA anticodon (3,5).…”

Polyphasic evidence delineating the root of life and roots of biological domains

“…This explanation is in accord with: (i) Ferroplasma, the only archaeon that uses an AUC three-anticodon combination to read any codon box, constitutes the unique archaeal source of the widely employed AUC anticodon combination in eukaryotic genomes, where it is utilized to read 67% of the single-amino acid codon boxes (Tong and Wong, 2004); (ii) the proposal that the cytoskeletal structure of Thermoplasma could be a preadaptation for eukaryotic cells (Searcy and Hixon, 1991); (iii) biochemical advantages of Thermoplasma as archaeal progenitor of Eukarya through an endosymbiotic event in a sulfide-rich environment (Margulis et al, 2006); (iv) EukaryaThermoplasmatales relationship suggested by supertree-based phylogenetic signal stripping (Pisani et al, 2007); (v) close resemblance between eukaryotic and archaeal tRNAs (Kwok and Wong, 1980;Xue et al, 1993;Guo et al, 2002); and (vi) dual, albeit unequal, resemblance of eukaryotic proteins toward archaeal and bacterial proteins (Esser et al, 2004).…”