Nucleoside triphosphatase activity associated with the N-terminal domain of mammalian tryptophanyl-tRNA synthetase.
Bovine tryptophanyl-tRNA synthetase (EC 6.1.1.2) deprived of Zn2+ by chelation with the phosphonate analog of Ap4A hydrolyzed ATP(GTP) to ADP(GDP) although its ability to form tryptophanyl adenylate was impaired. This hydrolytic activity is stimulated by Mg2+ and Mn2+ ions and inhibited by Zn2+. Monoclonal antibody Am1 against the N-terminal domain of the enzyme completely abolished ATP(GTP)ase activity. The core peptide generated after proteolytic splitting of the N-domain lacks this activity. We suggest that the nucleotide binding site(s) different from ATP sites involved in aminoacylation reaction reside(s) at the N-terminal domain(s) of the enzyme.
Kovaleva
G
G
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow.
Nikitushkina
T
T
Kisselev
L
L
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D002384:Catalysis; D002417:Cattle; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D006868:Hydrolysis; D007700:Kinetics; D008969:Molecular Sequence Data; D014369:Tryptophan-tRNA Ligase / Q000378:metabolism*
D000251:Adenosine Triphosphatases; D020558:GTP Phosphohydrolases; D014369:Tryptophan-tRNA Ligase