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Functional and structural analysis of acetylcholine receptor‐rich membranes after negative staining
Author(s) -
Reinhardt Sigrid,
Schmiady Hardi,
Tesche Bernd,
Hucho Ferdinand
Publication year - 1984
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(84)81050-9
Subject(s) - acetylcholine , membrane , chemistry , acetylcholine receptor , biophysics , staining , negative stain , microbiology and biotechnology , receptor , biochemistry , pharmacology , biology , medicine , pathology , electron microscope , physics , optics
Phosphotungstate (pH 7.4) used for negative staining of membranes from Torpedo electric tissue rich in acetylcholine receptor does not affect binding properties and cation permeability of the receptor and its ion channel. Uranyl salts, frequently used for negative staining, precipitate the receptor‐rich membranes making measurements of ligand binding and ion‐permeability regulation impossible. The gross ultrastructure in the two stains is not significantly different, but for future high‐resolution electron microscopy aiming at visualizing structural details of functional receptor molecules it is necessary to resort to a stain preserving native and active receptor. Uranyl salts are not applicable for this purpose. The electron micrographs obtained with phosphotungstate reveal two distinct structures in the receptor‐rich membrane: a closed ring (‘doughnut’) and an open ring (‘horseshoe’), with a ratio of abundance of about 3:2.