title: Catalytic and noncatalytic nucleotide binding sites of the Escherichia coli F1 ATPase. Amino acid sequences of beta-subunit tryptic peptides labeled with 2-azido-ATP.
abstract: Under appropriate conditions tight, noncovalent binding of 2-azido-adenine nucleotides to either catalytic or noncatalytic binding sites on the E. coli F1-ATPase occurs. After removal of unbound ligands, UV-irradiation results primarily in the covalent incorporation of nucleotide moieties into the beta-subunit in both catalytic and noncatalytic site labeling experiments. Minor labeling of the alpha-subunit was also observed. After trypsin digestion and purification of the labeled peptides, microsequencing studies identified two adjacent beta-subunit tryptic peptides labeled by 2-azido-ADP or -ATP. These beta-subunit peptides were labeled on tyrosine-331 (catalytic sites) and tyrosine-354 (noncatalytic sites) in homology with the labeling patterns of the mitochondrial and chloroplast enzymes.
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000378:metabolism; D000345:Affinity Labels; D000595:Amino Acid Sequence; D001386:Azides / Q000378:metabolism*; D001665:Binding Sites; D004926:Escherichia coli / Q000201:enzymology*; D010446:Peptide Fragments / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D014357:Trypsin
chemical_list: D000345:Affinity Labels; D001386:Azides; D010446:Peptide Fragments; C042231:2-azidoadenosine 5'-triphosphate; D000255:Adenosine Triphosphate; D014357:Trypsin; D006180:Proton-Translocating ATPases