Identification by cross-linking of a beta-bungarotoxin binding polypeptide in chick brain membranes.
beta-Bungarotoxin (beta-BTX) is a snake venom neurotoxin which inhibits neurotransmitter release from different types of nerve terminals. To identify presynaptic membrane components potentially important in neurosecretion, 125I-labeled beta-BTX (mol. wt. 21 000) was cross-linked to a high-affinity binding site in synaptic membrane fractions of chick brain using the photoactivable cross-linker N-succinimidyl-6(4'-azido-2'-nitrophenylamino)-hexanoate. Electrophoretic analysis of the cross-linked membrane proteins under both reducing and non-reducing conditions revealed a single [125I]beta-BTX-polypeptide adduct of apparent mol. wt. 116 000 (+/- 2000). The labeling of this band was prevented under conditions previously shown to inhibit the binding of [125I]beta-BTX to its high-affinity binding site. It is concluded that the cross-linking procedure identified a polypeptide of the presynaptic binding site for beta-BTX, and that this polypeptide has a mol. wt. of 95 000.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002038:Bungarotoxins / Q000378:metabolism*; D002352:Carrier Proteins / Q000302:isolation & purification*; D002645:Chickens; D003432:Cross-Linking Reagents; D008565:Membrane Proteins / Q000302:isolation & purification; D008970:Molecular Weight; D013570:Synaptic Membranes / Q000378:metabolism
D002038:Bungarotoxins; D002352:Carrier Proteins; D003432:Cross-Linking Reagents; D008565:Membrane Proteins