%0 Journal Article
%A Kondapuram, Mahesh
%A Frieg, Benedikt
%A Yüksel, Sezin
%A Schwabe, Tina
%A Sattler, Christian
%A Lelle, Marco
%A Schweinitz, Andrea
%A Schmauder, Ralf
%A Benndorf, Klaus
%A Gohlke, Holger
%A Kusch, Jana
%T Functional and structural characterization of interactions between opposite subunits in HCN pacemaker channels
%J bioRxiv beta
%C Cold Spring Harbor
%I Cold Spring Harbor Laboratory, NY
%M FZJ-2021-01114
%D 2020
%X Hyperpolarization-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.
%F PUB:(DE-HGF)16
%9 Journal Article
%R 10.1101/2020.09.21.305797
%U https://juser.fz-juelich.de/record/890666