Bukatoxin is an α-scorpion toxin found in the venom of the Chinese scorpion Buthus martensi Karsch.
[3] Specifically, the tripeptide segment 53 DKV 55, which forms a surface loop that is available for binding, is suggested to play a significant role in the blocking of the inactivation of sodium channels.
Other residues that could contribute to the binding of bukatoxin to the neurotoxin receptor site 3 of the sodium channels are the Val 1 and Asp 9, which reside in the same surface loop.
[1] The binding of bukatoxin is thought to lead to blocking of conformational changes in the sodium channel, by preventing the outward movement of the IVS4 transmembrane segment during depolarization.
[1][4][5] Muscle relaxation effects also arise in rabbit corpus cavernosum, but the mechanisms are not sodium channel-mediated and not completely elucidated yet.