Kondapuram, MaheshFrieg, BenediktYüksel, SezinSchwabe, TinaSattler, ChristianLelle, MarcoSchweinitz, AndreaSchmauder, RalfBenndorf, KlausGohlke, HolgerKusch, Jana2021-08-052021-08-052021-08-05https://researchdata.hhu.de/handle/entry/9810.25838/d5p-27Hyperpolarization-activated and cyclic nucleotide (HCN) modulated channels are tetrameric cation channels. In each of the four subunits, the intracellular cyclic nucleotide-binding domain (CNBD) is coupled to the transmembrane domain via a helical structure, the C-linker. High-resolution channel structures suggest that the C-linker enables functionally relevant interactions with the opposite subunit, which might be critical for coupling the conformational changes in the CNBD to the channel pore. We combined mutagenesis, patch-clamp technique, confocal patch-clamp fluorometry, and molecular dynamics simulations to show that residue K464 of the C-linker is essential for stabilizing the closed state of the mHCN2 channel by forming interactions with the opposite subunit. MD simulations revealed that both cAMP and K464E induce a rotation of the intracellular domain relative to the channel pore, weakening the autoinhibitory effect of the unoccupied CL-CNBD region. The adopted poses are in excellent agreement with structural results.enAttribution-NonCommercial-NoDerivs 3.0 United StatesHCN channelmolecular dynamics simulationssubunit interactionpatch-clamp techniqueconfocal patch-clamp fluorometryDataset