Possible exit gate in the drug binding domain of Pgp.
The transmembrane
helices of the drug binding domain of Pgp are shown as silver cartoons,
while the extramembranous protein is colored black. Alanine 841 (TM9),
V715 (TM7), and G722 (TM7) are shown in space-filling representation.
A841 is on the right-hand side of each figure, while V715 and G722
are on the left. V715 is above G722. From left to right are shown
the fully opened inward, partially opened inward, partially opened
outward, and fully opened outward conformations, respectively. A similar
figure with color-coded helices for ease of identification of individual
structures is presented in Figure S10 of the Supporting
Information.