title: Aminoacyl-tRNA synthetases from an extreme thermophile, Thermus thermophilus HB8.
abstract: Thermostable aminoacyl-tRNA synthetases specific to Val, Ile, Met and Glu were purified from an extreme thermophile, Thermus thermophilus HB8. As for the subunit compositions and molecular weights, these four aminoacyl-tRNA synthetases are similar to the corresponding enzymes from E. coli and B. stearothermophilus. Val-tRNA, Ile-tRNA and Met-tRNA synthetases from T. thermophilus have two tightly bound zinc ions, whereas Glu-tRNA synthetase does not. The amino acid compositions and secondary structures of Val-tRNA, Ile-tRNA and Met-tRNA synthetases are quite similar to one another. The conformational transition involving the anticodon of E. coli tRNAGlu as complexed with Glu-tRNA synthetase from T. thermophilus is necessary for the aminoacylation activity.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000604:Amino Acyl-tRNA Synthetases / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D013824:Thermus / Q000201:enzymology*
chemical_list: D000596:Amino Acids; D000604:Amino Acyl-tRNA Synthetases