Transmembrane topology of the acetylcholine receptor examined in reconstituted vesicles
Each of the five acetylcholine receptor (AChR) subunits, ..cap alpha../sub 2/..beta..-..gamma..delta, is believed to have the same number of transmembrane crossing and to share the same general folding pattern. AChR isolated from the electric organ of electric fish is predominantly dimeric. We have used this bridge as a marker for the C-terminus of the delta subunit, and presumably that of the other subunits in addition. The disulfide's accessibility to hydrophilic reductants, principally glutathione (GSH), was tested in a reconstituted vesicle system. The reduction of the delta-delta desulfide, as evidenced by the transition of AChrR dimers to monomers, was quantitatively monitored on velocity sedimentation sucrose gradients. Alternatively, the reduction of delta/sub 2/ to delta was followed by employing non-reducing SDS-PAGE. Reductants such as GSH were able to access the bridge in intact right-side-out vesicles. No acceleration of this process was evident when the vesicles were disrupted by freeze-thaw or by detergents. Control experiments which determined the rate of reduction of entrapped diphtheria toxin, or that of /sup 3/H-GSH efflux, demonstrated that intact reconstituted vesicles provide an adequate permeability barrier to GSH access of their intravesicular space.
- Research Organization:
- Yale Univ., New Haven, CT (USA)
- OSTI ID:
- 6994861
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
Similar Records
Pyridoxal phosphate as a probe of the cytoplasmic domains of transmembrane proteins: Application to the nicotinic acetylcholine receptor
The nicotinic acetylcholine receptor: Binding of nitroxide analogs of a local anesthetic and a photoactivatable analog of phosphatidylserine
Related Subjects
ACETYLCHOLINE
RECEPTORS
CELL MEMBRANES
PERMEABILITY
ELECTROPHORESIS
FISHES
GLUTATHIONE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
AMINES
AMMONIUM COMPOUNDS
ANIMALS
AQUATIC ORGANISMS
AUTONOMIC NERVOUS SYSTEM AGENTS
CELL CONSTITUENTS
DRUGS
ESTERS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MEMBRANE PROTEINS
MEMBRANES
NEUROREGULATORS
ORGANIC COMPOUNDS
PARASYMPATHOMIMETICS
PEPTIDES
POLYPEPTIDES
PROTEINS
QUATERNARY COMPOUNDS
RADIOPROTECTIVE SUBSTANCES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques