Fig. 6: Rosetta models for activation and inactivation of spHCN channels and their regulation by cAMP.
From: Electromechanical coupling mechanism for activation and inactivation of an HCN channel
a–d Modeled structures (side view and bottom view) highlighting the rearrangement of the C-linker region of one subunit relative to the S4 and S5 helices of the adjacent subunit for four states: resting-cAMP (a), activated (b), resting-apo (c), and inactivated (d). The S4 helix moves downward and bends into two segments after hyperpolarization in both activated and inactivated states. The bottom view highlights the rigid-body rotational movements of the C-linker around the central axis of the pore in the absence of cyclic nucleotide. See also Supplementary Movies 1–4.
