title: [Role of arginine residues in phenylalanyl-tRNA synthetase interaction with substrates].
abstract: The effect of 2,4-pentandione on the activity of phenylalanyl-tRNA synthetase (Phe-RSase) from E. coli MRE-600 was investigated. Modification of arginine residues of Phe-RSase with 2,4-pentandione was shown to decrease the rate of both ATP-[32P]pyrophosphate exchange and aminoacylation reaction. In the presence of Mg2+ ions ATP essentially protects the enzyme from inactivation. L-Phe has practically no protective effect. There are no changes in the values of Km for tRNAPhe in the aminoacylation reaction and for amino acid in ATP-[32P]pyrophosphate exchange and aminoacylation reaction while Km for ATP is increased in both. Modification of 42-44 arginine residues per molecule of the enzyme causes loss of 50% of the enzyme activity for tRNA aminoacylation. Under these conditions ATP in the presence of Mg2+ ions as well as ATP + Mg2+ combined with L-Phe, protects 8-10 arginine residues per molecule of the enzyme from modification. Part of arginine residues of the enzyme molecule is assumed to be essential for ATP binding.
mesh_terms: D000255:Adenosine Triphosphate; D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D001120:Arginine; D004926:Escherichia coli / Q000201:enzymology; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D010422:Pentanones / Q000494:pharmacology; D010652:Phenylalanine-tRNA Ligase / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D010422:Pentanones; C008790:acetylacetone; D000255:Adenosine Triphosphate; D001120:Arginine; D000604:Amino Acyl-tRNA Synthetases; D010652:Phenylalanine-tRNA Ligase; D008274:Magnesium
vernacular_title: Rol' ostatkov arginina vo vzaimodeĭstvii fenilalanil-tRNK-sintetazy s substratami.