Nucleoside triphosphatase activity associated with the N‐terminal domain of mammalian tryptophanyl‐tRNA synthetase

[摘要]

Bovine tryptophanyl-tRNA synthetase (EC 6.1.1.2) deprived of Zn²⁺ by chelation with the phosphonate analog of Ap₄A hydrolized 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 Aml 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.

[学科分类] 生物化学/生物物理

[关键词] Mammalian aminoacyl-tRNA synthetase;ATP/GTP hydrolysis;Non-canonical enzymatic activity;Zn2+ chelation;Ap4A phosphonate analog;aaRS;aminoacyl-tRNA synthetase;Ap3A;P1;P3-bis(5'-adenosyl)triphosphate;Ap4A;P1;P4-bis(5'-adenosyl)tetraphosphate;ATP(GTP)ase;adenosine (guanosine) triphosphatase;GlyRS;glycyl-tRNA synthetase;E(Trp ~ AMP);tryptophanyl adenylate enzyme complex;E(−Zn);Zn2+-deprived enzyme;mAbs;monoclonal antibodies;PEI-cellulose;polyethylene iminocellulose;PheRS;phenylalanyl-tRNA synthetase;TrpRS;tryptophanyl-tRNA synthetase