Figure 3.

(A) The proton conduction pathway seen in a 1.65-Å resolution crystal structure including three clusters of crystallographic waters. (B–D) A second perspective of the outer (B), bridging (C), and exit (D) clusters viewed normal to the membrane plane. (E) The surface of the pore (light blue shading) is shown along with the crystallographic waters (red spheres). Val27, His37, and Trp41 residues are rendered in blue, orange, and magenta, respectively. Pore radius profiles are plotted for the high-resolution crystal structure (3LBW, blue solid line), low-pH (3C9J, blue dash-dotted line), and amantadine-inhibited (red dashed line) structures.