Analysis by low-angle neutron scattering of the structure of the acetylcholine receptor from Torpedo californica in detergent solution

Journal Article · Fri Nov 30 23:00:00 EST 1979 · Biophys. J.; (United States)

DOI:https://doi.org/10.1016/S0006-3495(79)85194-2· OSTI ID:5592835

Wise, D S ^[1]; Karlin, A; Schoenborn, B P

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1. Columbia Univ., New York

The acetylcholine receptor from the electric tissue of Torpedo californica is a large, integral membrane protein containing four different types of polypeptide chains. In this paper the results of the use of low-angle neutron scattering to investigate the shape of the receptor-detergent complex and separately of its protein and detergent moieties are reported. By adjustment of the neutron-scattering density of the solvent with D/sub 2/O to match that of one or the other of the moieties, its contribution to the scattering can be nearly, if not completely, eliminated. Neutron scattering from Triton X-100 micelles established that this detergent is contrast matched in 18% D/sub 2/O. Scattering measurements on the receptor-detergent complex in this solvent yielded a radius of gyration of the acetylcholine receptor monomer of 46 +- 1 A. The radius of gyration and molecular volume (305,000 A/sup 3/) of the receptor is inconsistent with a compact spherical shape. These parameters are consistent with, for example, a prolate cylinder of dimensions (length x diameter) 150 x 50 A or an oblate cylinder, 25 x 130 A. More complex shapes are possible and in fact seem to be required to reconcile the present results with previous electron microscopic and x-ray analyses of receptor in membrane and with considerations of the function of the receptor in controlling ion permeability. The neutron-scattering data yield, in addition, an independent determination of the molecular weight of the receptor protein (240,000 +- 40,000), the extent of Triton X-100 binding in the complex (0.4 g/g protein), and from the extended scattering curve, an approximation to the shape of the receptor-Triton X-100 complex, namely an oblate ellipsoid of axial ratio 1:4.

• OSTI ID: 5592835
• Journal Information: Biophys. J.; (United States), Journal Name: Biophys. J.; (United States) Vol. 28:3; ISSN BIOJA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACETYLCHOLINE
ADDITIVES
AMINES
AMMONIUM COMPOUNDS
ANIMALS
AQUATIC ORGANISMS
BARYONS
BODY
COMPLEXES
DETERGENTS
DRUGS
ELEMENTARY PARTICLES
EMULSIFIERS
ESTERS
FERMIONS
FISHES
HADRONS
HEAVY WATER
HYDROGEN COMPOUNDS
MOLECULAR STRUCTURE
MOLECULAR WEIGHT
MONOMERS
NEUTRONS
NUCLEONS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PARASYMPATHOMIMETICS
PEPTIDES
POLYPEPTIDES
PROTEINS
QUATERNARY COMPOUNDS
RECEPTORS
SCATTERING
STRUCTURAL CHEMICAL ANALYSIS
SURFACTANTS
TISSUES
VERTEBRATES
WATER
WETTING AGENTS