Structure of acetylcholine receptor dimer determined by neutron scattering and electron microscopy
- Columbia Univ., New York, NY
Previous work has shown that the predominant native form of the acetylcholine receptor from the electric tissue of Torpedo californica is a dimer of M/sub r/ = 500,000, cross-linked by a disulfide bond between the largest (delta) of the five chains (..cap alpha../sub 2/..beta gamma..delta) that comprise the monomer. Small-angle neutron scattering of purified receptor dimer in Triton X-100 solution containing 18% D/sub 2/O, in which the Triton X-100 is contrast-matched, yields a radius of gyration of the dimer of 66 A. Based on the assumptions that the dimer is symmetrical and that the radius of gyration of the monomer does not change in forming dimer, this value, together with the radius of gyration of the receptor monomer (46 A), determined previously, allows the calculation of the distance separating the centers of neutron scattering density of monomers in a dimer; the result is 96 A. Electron microscopy of negatively stained dimers permits an independent measurement of the distance between the apparent centers of mass of the monomers; the average is 96 A, in agreement with the result of the neutron scattering analysis. The electron micrographs of dimer also permit the location of the delta chains at the region of contact of the monomers. A model for the receptor dimer consistent with all available structural information is presented.
- OSTI ID:
- 6583067
- Journal Information:
- J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 256:7; ISSN JBCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
551000 -- Physiological Systems
59 BASIC BIOLOGICAL SCIENCES
ACETYLCHOLINE
AMINES
AMMONIUM COMPOUNDS
ANIMAL TISSUES
ANIMALS
AQUATIC ORGANISMS
AUTONOMIC NERVOUS SYSTEM AGENTS
BODY
DIMERS
DRUGS
EEL
ELECTRON MICROSCOPY
ESTERS
FISHES
HEAVY WATER
HYDROGEN COMPOUNDS
MICROSCOPY
NEUROREGULATORS
NEUTRON SPECTROSCOPY
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PARASYMPATHOMIMETICS
QUATERNARY COMPOUNDS
RECEPTORS
SCATTERING
SMALL ANGLE SCATTERING
SPECTROSCOPY
STRUCTURAL CHEMICAL ANALYSIS
TISSUES
VERTEBRATES
WATER