%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 Communications biology
%V 5
%N 1
%@ 2399-3642
%C London
%I Springer Nature
%M FZJ-2022-02208
%P 430
%D 2022
%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 (MD) simulations to show that residue K464 of the C-linker is relevant for stabilizing the closed state of the mHCN2 channel by forming interactions with the opposite subunit. MD simulations revealed that in the K464E channel, a rotation of the intracellular domain relative to the channel pore is induced, which is similar to the cAMP-induced rotation, weakening the autoinhibitory effect of the unoccupied CL-CNBD region. We suggest that this CL-CNBD rotation is considerably involved in activation-induced affinity increase but only indirectly involved in gate modulation. The adopted poses shown herein are in excellent agreement with previous structural results.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ 35534535
%U <Go to ISI:>//WOS:000792648600004
%R 10.1038/s42003-022-03360-6
%U https://juser.fz-juelich.de/record/907779