Figure 1
From: A single active catalytic site is sufficient to promote transport in P-glycoprotein
UIC2 mAb binding to Staphylococcus alpha toxin permeabilized NIH 3T3 cells expressing wild-type Pgp in the presence of ATP/Mg2+ (a) ATP in the absence of Mg2+ (b) AMP-PNP/Mg2+ (c) or ATP/Mg2+ at 4 °C (d). Permeabilized cells were treated with nucleotides at different concentrations for 20 min and then labeled with UIC2-A647 for another 30 min (a–c) or 40 min (d) without washing out the nucleotides. In case of Vi treatment un-trapped nucleotides were washed out in the presence of Vi. UIC2-A647 fluorescence intensities were plotted as a function of nucleotide concentration and fitted with a four parameter Hill function to determine the apparent affinities of nucleotide binding (KA) and Hill slope values (see Materials and Methods).
