Figure 6.

Effects of ATP binding and ATP hydrolysis on the conformational changes of P-gp. A and B, proximity ratio in permeabilized semi-intact cells treated with 100 μm verapamil (blue) or DMSO (empty) in the presence 4.5 mm MgATP. The proximity ratios in the absence of ATP are shown in the hatched plots. C, proximity ratio in permeabilized semi-intact cells in the presence of 4.5 mm MgATP (empty), 4.5 mm MgAMP-PNP (green), or 4.5 mm MgATP and 1 mm orthovanadate (magenta). The proximity ratio is shown relative to that of P-gp–FRET in the presence of MgATP. n = 12–15 cells per sample; **, p < 0.01; ***, p < 0.001; N.S., p > 0.05.