ATP binding in peptide synthetases: determination of contact sites of the adenine moiety by photoaffinity labeling of tyrocidine synthetase 1 with 2-azidoadenosine triphosphate

The technique of photo affinity labeling of tyrocidine synthetase 1(TY1) with 2-azidoadenosine triphosphate (2-azido-ATP), applied in the study of a nucleotide binding domain in peptide synthetases, revealed a loss of catalytic activity and a time dependent covalent modification of the enzyme when TY1 was exposed to ultra-violet radiation in the presence of photolabel. The components of the nucleotide binding domain were observed near the adenine ring in ATP.