Electron microscopy of complexes of isolated acetylcholine receptor, biotinyl-toxin, and avidin

Journal Article · Fri Jan 01 00:00:00 EST 1982 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.79.2.310· OSTI ID:5674874

Holtzman, E ^[1]; Wise, D; Wall, J; Karlin, A

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1. Columbia Univ., New York

The principal curarimimetic toxin of Naja naja siamensis derivatized with biothinyl groups binds specifically both to acetylcholine receptor, isolated from Torpedo californica electric tissue, and to avidin. Isolated complexes of receptor monomer or dimer, biotinyl-toxin, and avidin were negatively stained and examined in the scanning transmission electron microscope. We measured the angle made by the radius to each avidin bound at the periphery of a monomeric unit in dimer to the axis connecting the centers of the monomers, starting at the crosslink between the monomers. We infer from the distribution of these angles that one toxin binding site is located in the range of 45/sup 0/ to 85/sup 0/ and another at about 100/sup 0/ further from the crosslink between the monomers. Because it is known that there are two toxin binding sites per monomer, associated with the two ..cap alpha.. chains, the bound avidins presumably point to portions of the ..cap alpha.. chains, indicating their positions relative to that portion of the delta chain located at the crosslink between monomers in dimer.

• OSTI ID: 5674874
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 79:2
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
RECEPTORS
STRUCTURAL CHEMICAL ANALYSIS
ACETYLCHOLINE
BINDING ENERGY
COMPLEXES
CROSS-LINKING
DIMERS
ELECTRON MICROSCOPY
ELECTRON SCANNING
FISHES
POLYPEPTIDES
SNAKES
TOXINS
AMINES
AMMONIUM COMPOUNDS
ANIMALS
ANTIGENS
AQUATIC ORGANISMS
AUTONOMIC NERVOUS SYSTEM AGENTS
CHEMICAL REACTIONS
DRUGS
ENERGY
ESTERS
MATERIALS
MICROSCOPY
NEUROREGULATORS
ORGANIC COMPOUNDS
PARASYMPATHOMIMETICS
PEPTIDES
POLYMERIZATION
PROTEINS
QUATERNARY COMPOUNDS
REPTILES
TOXIC MATERIALS
VERTEBRATES
550200* - Biochemistry