title: A peptide from the extension of Lys-tRNA synthetase binds to transfer RNA and DNA.
abstract: Eukaryotic aminoacyl-tRNA synthetases have dispensable extensions appended at the amino- or carboxyl-terminus as compared to their bacterial counterparts. While a synthetic peptide corresponding to the basic amino-terminal extension in yeast Asp-tRNA synthetase binds to DNA, the extension in the intact protein evidently binds to tRNA and enhances the tRNA specificity of Asp-tRNA synthetase. On the other hand, the amino-terminal extension in human Asp-tRNA synthetase, both within the intact protein and as a synthetic peptide, binds to tRNA. Here, the tRNA binding of a synthetic peptide, hKRS(Arg(25)-Glu(42)), corresponding to the amino-terminal extension of human Lys-tRNA synthetase (hKRS) was analyzed. This basic peptide bound to tRNA(Phe) and the apparent-binding constant increased with increasing concentrations of Mg(2+). The hKRS peptide also bound to DNA and polyphosphate; however, the apparent DNA-binding constants decreased at increasing concentrations of Mg(2+). The ability of the hKRS peptide to adopt alpha-helical conformation was demonstrated by NMR and circular dichroism. A Lys-rich peptide derived from the elongation factor 1alpha was also examined and bound to DNA but not to tRNA.
mesh_terms: D000595:Amino Acid Sequence; D002413:Cations, Divalent / Q000737:chemistry; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008250:Lysine-tRNA Ligase / Q000737:chemistry*; D015636:Magnesium Chloride / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D020648:Peptide Elongation Factor 1 / Q000737:chemistry; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D011122:Polyphosphates / Q000737:chemistry; D011485:Protein Binding; D017433:Protein Structure, Secondary; D012343:RNA, Transfer / Q000737:chemistry / Q000378:metabolism*; D012358:RNA, Transfer, Met / Q000737:chemistry / Q000378:metabolism; D012360:RNA, Transfer, Phe / Q000737:chemistry / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D012965:Sodium Chloride / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014270:Trifluoroethanol / Q000737:chemistry
chemical_list: D002413:Cations, Divalent; D004268:DNA-Binding Proteins; D020648:Peptide Elongation Factor 1; D010455:Peptides; D011122:Polyphosphates; D012358:RNA, Transfer, Met; D012360:RNA, Transfer, Phe; D016601:RNA-Binding Proteins; D015636:Magnesium Chloride; D012965:Sodium Chloride; D014270:Trifluoroethanol; D004247:DNA; D012343:RNA, Transfer; D008250:Lysine-tRNA Ligase