Single-Particle Cryo-EM of an Innexin Gap Junction Channel at Atomic Resolution
Abstract: Gap junction channels mediate intercellular communication, enabling electrical and chemical coupling between adjacent cells. Two gene families are known to form these channels: connexin in chordates, including vertebrates, and innexin in invertebrates. The genetic correlation is unclear, however, because these two families do not show significant sequence similarity. Recently, we determined an atomic structure of the Caenorhabditis elegans innexin-6 (INX-6) by single-particle cryo-EM. The INX-6 structure exhibited high structural similarity to connexin-26 in terms of the monomeric arrangement and N-terminal funnel, but had a different subunit number. In this review, the structural properties of the INX-6 atomic model and the cryo-EM sample preparation procedure essential for this study are comprehensively summarized.
Key words: gap junction, innexin, cryo-electron microscopy (cryo-EM), single particle analysis, sample preparation for cryo-EM