We acknowledge the European Synchrotron Radiation Facility for provision of beam time on CM01 and we would like to thank Dr Gregory Effantin for assistance. The authors also gratefully acknowledge the computing time provided to them on the high-performance computer Lichtenberg at the NHR Centers NHR4CES at TU Darmstadt. This is funded by the Federal Ministry of Education and Research, and the state governments participating on the basis of the resolutions of the GWK for national high- performance computing at universities. The work was partially funded by Telethon grant no. GGP20021, Prin 2022 grant no. 2022EMA8FA and Fondation Leducq Research Grant no. 19CVD03 to AM, by Deutsche Forschungsgemeinschaft under grant no. HA5261/6-1 to J.K. and K.H., by by Deutsche Forschungsgemeinschaft under grant no. TH558/34-1 to G.T. and by Cariplo Young Investigator grant no. 2018–0231 to A.S. We are grateful to the U. of Milano NOLIMITS Center and to Fondazione Romeo and Enrica Invernizzi, Pediatric Research Center, for continuous support.

Dataset underlying findings published in:"Structural determinants of ivabradine block of the open pore of HCN4", PNAS (DOI: https://doi.org/10.1073/pnas.2402259121)