Structural and functional studies of gap junction channels.
X-ray analysis of the human connexin26 gap junction channel has provided structural details of its open state. The gap junction channel is formed by paired hemichannels on two adjacent cells; each hemichannel consists of six protomers, and exhibits a six-fold symmetry. The protomer folds in a typical four-helix bundle. The amino-terminal region folds in a short helix and is inserted into the lumen to form a funnel structure. The structure of the amino-terminal region could explain the channel's gating mechanism. Extensive interactions between two hemichannels allow the gap junction channel to tightly connect two adjacent cells. The gap junction, which consists of hundreds of gap junction channels, could both serve as an intracellular channel and contribute to cellular adhesion.
Nakagawa
So
S
Institute for Protein Research, Osaka University, OLABB, 6-2-3 Furuedai, Suita 565-0874, Japan.
Maeda
Shoji
S
Tsukihara
Tomitake
T
D000595:Amino Acid Sequence; D000818:Animals; D000072259:Connexin 26; D017630:Connexins / Q000737:chemistry* / Q000378:metabolism*; D004553:Electric Conductivity; D006801:Humans; D015640:Ion Channel Gating; D008969:Molecular Sequence Data; D016062:Porosity; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary
D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26