Ultrastructure of the 5-hydroxytryptamine3 receptor.
We have determined the ultrastructure of 5-hydroxytryptamine3 (5-HT3) serotonin receptors purified from NG108-15 mouse neuroblastoma x rat glioma cells by electron microscopic examination of receptor particles embedded in uranyl acetate stain and metal replicas of rapidly frozen receptors. The 5-HT3 receptor can be modelled as a cylinder 11 nm in length and 8 nm in diameter with a closed end and a central cavity 3 nm in diameter. Analysis of the rotational symmetry of single receptor particles indicates that the 5-HT3 receptor is composed of five subunits arranged symmetrically around a central cavity. Together with evidence obtained for related proteins in other studies using ultrastructural, biochemical, or electrophysiological methods, our observations suggest that all members of the ligand-gated ion channel superfamily may possess a pentameric quaternary structure.
Boess
F G
FG
MRC Molecular Neurobiology Unit, Cambridge, England.
Beroukhim
R
R
Martin
I L
IL
D000818:Animals; D006822:Hybrid Cells; D015640:Ion Channel Gating; D051379:Mice; D008854:Microscopy, Electron; D011487:Protein Conformation; D051381:Rats; D011985:Receptors, Serotonin / Q000648:ultrastructure*
D011985:Receptors, Serotonin