title: Intron positions delineate the evolutionary path of a pervasively appended peptide in five human aminoacyl-tRNA synthetases.
abstract: Recent progress in genome sequencing has revealed a correspondence between the evolution of multicellularity and the appending of new peptides onto age-old enzyme bodies. Indicative of the pervasive nature of these appended peptides, in some cases the same sequences have been appended to a number of different enzymes. By analyzing the positions of introns within one such roaming peptide, an approximately 50-amino acid motif appended to five human aminoacyl-tRNA synthetases, I have delineated its path in eukaryote evolution. The motif was first acquired as an N-terminal extension by histidyl- and glycyl-tRNA synthetases at a very early stage of eukaryote evolution. Later, but not less than 1200 million years ago, the motif spread from histidyl-tRNA synthetase to the C and N terminals of glutamyl- and prolyl-tRNA synthetase, respectively, and then spread further during the evolution of the Chordate lineage to the N terminal of tryptophanyl-tRNA synthetase. In similar fashion, the motif in glycyl-tRNA synthetase spread to the C terminal of methionyl-tRNA synthetase not later than 1000 million years ago.
authors.affiliation: Department of Protein Engineering, Cancer Institute, Japanese Foundation for Cancer Research, 1-37-1, Kami-Ikebukuro, Toshima, Tokyo 170-8455, Japan. kshiba@jfcr.or.jp
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Shiba
mesh_terms: D000595:Amino Acid Sequence; D000604:Amino Acyl-tRNA Synthetases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019143:Evolution, Molecular; D007438:Introns; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
chemical_list: D000604:Amino Acyl-tRNA Synthetases