title: ATP-binding properties of P glycoprotein from multidrug-resistant KB cells.
abstract: The photoaffinity reagent 8-azido-alpha-[32P]ATP was used to label a protein of 170 kDa in membrane vesicle preparations from a highly multidrug-resistant cell line, KB-V1, but not from the drug-sensitive parental cell line KB-3-1. The 170-kDa labeled protein was immunoprecipitated with a monoclonal antibody (MRK-16) to P glycoprotein. Both ATP and GTP inhibited labeling by 8-azido-alpha-[32P]ATP. Labeling of P170 was not inhibited by 5 mM ADP, 5 mM ribose-5-phosphate, or 100 microM vinblastine. These data directly demonstrate that P glycoprotein has a nucleotide-binding site that could supply energy for drug transport.
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000378:metabolism; D000345:Affinity Labels / Q000378:metabolism*; D001386:Azides / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004351:Drug Resistance; D006023:Glycoproteins / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D007624:KB Cells; D008970:Molecular Weight; D010777:Photochemistry; D011485:Protein Binding; D012267:Ribosemonophosphates / Q000378:metabolism
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000345:Affinity Labels; D001386:Azides; D006023:Glycoproteins; D012267:Ribosemonophosphates; C031626:ribose-5-phosphate; C017040:8-azidoadenosine 5'-triphosphate; D000244:Adenosine Diphosphate; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate