Molecular architecture of a retinal cGMP-gated channel: the arrangement of the cytoplasmic domains.
Cyclic nucleotide-gated (CNG) channels play a central role in the conversion of sensory information, such as light and scent, into primary electrical signals. We have purified the CNG channel from bovine retina and have studied it using electron microscopy and image processing. We present the structure of the channel to 35 A resolution. This three-dimensional reconstruction provides insight into the architecture of the protein, suggesting that the cyclic nucleotide-binding domains, which initiate the response to ligand, 'hang' below the pore-forming part of the channel, attached by narrow linkers. The structure also suggests that the four cyclic nucleotide-binding domains present in each channel form two distinct domains, lending structural weight to the suggestion that the four subunits of the CNG channels are arranged as a pair of dimers.
Higgins
Matthew K
MK
MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
Weitz
Dietmar
D
Warne
Tony
T
Schertler
Gebhard F X
GF
Kaupp
U Benjamin
UB
D000818:Animals; D002417:Cattle; D054815:Cyclic Nucleotide-Gated Cation Channels; D007473:Ion Channels / Q000737:chemistry* / Q000502:physiology / Q000648:ultrastructure; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000502:physiology; D012374:Rod Cell Outer Segment / Q000737:chemistry* / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology
D054815:Cyclic Nucleotide-Gated Cation Channels; D007473:Ion Channels