A Multifunctional Repeated Motif Is Present in Human Bifunctional tRNA Synthetase

• Published in: The Journal of biological chemistry 1998-05, Vol.273 (18), p.11267-11273
• Main Authors: Rho, Seung Bae, Lee, Jong Sang, Jeong, Eui-Jun, Kim, Key-Sun, Kim, Yang Gyun, Kim, Sunghoon
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino Acyl-tRNA Synthetases - chemistry; Amino Acyl-tRNA Synthetases - metabolism; Animals; Calorimetry, Differential Scanning; Drosophila melanogaster; Glutamate-tRNA Ligase - chemistry; Glutamate-tRNA Ligase - metabolism; Helix-Turn-Helix Motifs; Humans; Isoleucine-tRNA Ligase - metabolism; Magnetic Resonance Spectroscopy; Molecular Sequence Data; Nucleic Acids - metabolism; Protein Binding; Protein Conformation
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.273.18.11267

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 °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 μm. 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.