Profile of the alpha-bungarotoxin-binding regions on the extracellular part of the alpha-chain of Torpedo californica acetylcholine receptor.
The continuous alpha-neurotoxin-binding regions on the extracellular part (residues 1-210) of the alpha-chain of Torpedo californica acetylcholine receptor were localized by reaction of 125I-labelled alpha-bungarotoxin with synthetic overlapping peptides spanning this entire part of the chain. The specificity of the binding was confirmed by inhibition with unlabelled toxin and, for appropriate peptides, with unlabelled anti-(acetylcholine receptor) antibodies. Five toxin-binding regions were localized within residues 1-10, 32-41, 100-115, 122-150 and 182-198. The third, fourth and fifth (and to a lesser extent the first and second) toxin-binding regions overlapped with regions recognized by anti-(acetylcholine receptor) antibodies. The five toxin-binding regions may be distinct sites or, alternatively, different 'faces' in one (or more) sites.
Marrs McLean Department of Biochemistry, Baylor College of Medicine, Houston, TX 77030.
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Mulac-Jericevic
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Atassi
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D001665:Binding Sites; D002038:Bungarotoxins / Q000378:metabolism; D018680:Cholinergic Antagonists; D003039:Cobra Neurotoxin Proteins / Q000378:metabolism; D005110:Extracellular Space / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D011950:Receptors, Cholinergic / Q000276:immunology / Q000378:metabolism*; D011978:Receptors, Nicotinic; D014101:Torpedo / Q000378:metabolism*; D064569:alpha7 Nicotinic Acetylcholine Receptor
D000906:Antibodies; D002038:Bungarotoxins; D018680:Cholinergic Antagonists; D003039:Cobra Neurotoxin Proteins; D010455:Peptides; D011950:Receptors, Cholinergic; D011978:Receptors, Nicotinic; D064569:alpha7 Nicotinic Acetylcholine Receptor