title: A multifunctional repeated motif is present in human bifunctional tRNA synthetase.
abstract: Tandem repeats located in the human bifunctional glutamyl-prolyl-tRNA synthetase (EPRS) have been found in many different eukaryotic tRNA synthetases and were previously shown to interact with another distinct repeated motifs in human isoleucyl-tRNA synthetase. Nuclear magnetic resonance and differential scanning calorimetry analyses of an isolated EPRS repeat showed that it consists of a helix-turn-helix with a melting temperature of 59 degrees C. Specific interaction of the EPRS repeats with those of isoleucyl-tRNA synthetase was confirmed by in vitro binding assays and shown to have a dissociation constant of approximately 2.9 microM. The EPRS repeats also showed the binding activity to the N-terminal motif of arginyl-tRNA synthetase as well as to various nucleic acids, including tRNA. Results of the present work suggest that the region comprising the repeated motifs of EPRS provides potential sites for interactions with various biological molecules and thus plays diverse roles in the cell.
authors.affiliation: Department of Biology, Sung Kyun Kwan University, 300 Chunchundong, Jangangu, Suwon, Kyunggido 440-746, Korea.
authors.forename: S B
authors.initials: SB
authors.lastname: Rho
authors.forename: J S
authors.initials: JS
authors.lastname: Lee
authors.forename: E J
authors.initials: EJ
authors.lastname: Jeong
authors.forename: K S
authors.initials: KS
authors.lastname: Kim
authors.forename: Y G
authors.initials: YG
authors.lastname: Kim
authors.forename: S
authors.initials: S
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D000604:Amino Acyl-tRNA Synthetases / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D002152:Calorimetry, Differential Scanning; D004331:Drosophila melanogaster; D005975:Glutamate-tRNA Ligase / Q000737:chemistry* / Q000378:metabolism; D019077:Helix-Turn-Helix Motifs; D006801:Humans; D007533:Isoleucine-tRNA Ligase / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009696:Nucleic Acids / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D009696:Nucleic Acids; D000604:Amino Acyl-tRNA Synthetases; C100134:prolyl T RNA synthetase; D005975:Glutamate-tRNA Ligase; D007533:Isoleucine-tRNA Ligase