Cryo-EM structures of undocked innexin-6 hemichannels in phospholipids
Batuujin Burendei, Ruriko Shinozaki, Masakatsu Watanabe, Tohru Terada, Kazutoshi Tani, Yoshinori Fujiyoshi, Atsunori Oshima
Abstract
innexin-6 (INX-6) gap junction proteins in an undocked hemichannel form. In the nanodisc-reconstituted structure of the wild-type INX-6 hemichannel, flat double-layer densities obstruct the channel pore. Comparison of the hemichannel structures of a wild-type INX-6 in detergent and nanodisc-reconstituted amino-terminal deletion mutant reveals that lipid-mediated amino-terminal rearrangement and pore obstruction occur upon nanodisc reconstitution. Together with molecular dynamics simulations and electrophysiology functional assays, our results provide insight into the closure of the INX-6 hemichannel in a lipid bilayer before docking of two hemichannels.