Cornwell M M, Tsuruo T, Gottesman M M, Pastan I
FASEB J. 1987 Jul;1(1):51-4. doi: 10.1096/fasebj.1.1.2886389.
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.
光亲和试剂8-叠氮-α-[32P]ATP被用于标记来自高度多药耐药细胞系KB-V1的膜囊泡制剂中的一种170 kDa的蛋白质，但不能标记来自药物敏感亲本细胞系KB-3-1的膜囊泡制剂。用针对P糖蛋白的单克隆抗体（MRK-16）免疫沉淀170 kDa的标记蛋白。ATP和GTP均抑制8-叠氮-α-[32P]ATP的标记作用。5 mM ADP、5 mM核糖-5-磷酸或100 μM长春碱不抑制P170的标记。这些数据直接表明P糖蛋白有一个可为药物转运提供能量的核苷酸结合位点。
