Relative locations of the. beta. and delta chains of the acetylcholine receptor determined by electron microscopy of isolated receptor trimer. [Fishes, electric tissue]
- Brookhaven National Lab., Upton, NY
The monomeric unit of the acetylcholine receptor of electric tissue of Torpedo californica has previously been shown to have a subunit composition of ..cap alpha../sub 2/..beta gamma..delta. Receptor in membrane isolated from Torpedo electric tissue occurs as both monomer and dimer. In the dimer, which is the predominant form, the monomeric units are cross-linked via a disulfide bond between delta chains. The addition of diamide to receptor-rich membrane causes the formation of trimer and higher oligomers in which the monomeric units are linked by disulfide bonds alternately between pairs of delta chains and between pairs ..beta.. chains. We have isolated receptor trimer and determined the relative locations of the monomeric units by scanning transmission electron microscopy of negatively stained preparations. In face view, the trimer appears as three approximately 90 angstrom disks, each with a central, densely staining pit. From the angles of the triangle formed by the lines connecting the centers of the monomers in the trimer, we infer that the ..beta..-..beta.. disulfide bond is separated from the delta-delta disulfide bond by an angle in the range of 50-80/sup 0/.
- OSTI ID:
- 5212434
- Journal Information:
- J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 256:24; ISSN JBCHA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Electron microscopy of complexes of isolated acetylcholine receptor, biotinyl-toxin, and avidin
Topographical studies of the nicotinic acetylcholine receptor. [Torpedo californica]
Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ACETYLCHOLINE
AMIDES
AMINES
AMMONIUM COMPOUNDS
ANIMALS
AQUATIC ORGANISMS
AUTONOMIC NERVOUS SYSTEM AGENTS
CHEMICAL BONDS
CHEMICAL REACTIONS
CROSS-LINKING
DIMERS
DISULFIDES
DRUGS
ELECTRON MICROSCOPY
ESTERS
FISHES
MEMBRANES
MICROSCOPY
NEUROREGULATORS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PARASYMPATHOMIMETICS
POLYMERIZATION
QUATERNARY COMPOUNDS
RECEPTORS
SCANNING ELECTRON MICROSCOPY
VERTEBRATES