Figure 8.

Structural summary of the light-induced helical movements observed in DeNaR. In the presence of K⁺ (left), we observed an outward lateral tilt of helix F away from both helices B and G and an outward lateral tilt of helix G (cytoplasmic view). In the presence of Na⁺ (right), we observed an outward movement of helix F, an outward movement of helix G, and a clockwise rotation of helix F relative to helix G. In the presence of K⁺, DeNaR undergoes a BR-like rearrangement that is consistent with the H⁺ pumping activity observed under those conditions. In the presence of Na⁺, helix F undergoes a rotation that is the opposite of that in BR.