title: Two configurations of a channel-forming membrane protein.
abstract: The protein oligomer forming the gap junction channel has been analysed in two Ca2+-sensitive states by electron microscopy of membranes in frozen aqueous solutions. Switching between states occurs by a small cooperative rearrangement involving tilting of the subunits, which may be responsible for the effect of Ca2+ on channel permeability in vivo.
mesh_terms: D000818:Animals; D002118:Calcium / Q000502:physiology; D017630:Connexins; D007365:Intercellular Junctions / Q000502:physiology / Q000648:ultrastructure*; D008099:Liver / Q000648:ultrastructure; D008565:Membrane Proteins; D051381:Rats; D014961:X-Ray Diffraction
chemical_list: D017630:Connexins; D008565:Membrane Proteins; D002118:Calcium