Kappa-bungarotoxin

Kappa-bungarotoxin
The three-dimensional structure of α-bungarotoxin, highlighting disulfide bonds, from PDB: 1KBA​.
Identifiers
Organism	Bungarus multicinctus
Symbol	N/A
UniProt	P01398

Kappa-bungarotoxin (often written κ-Bgt; historically also called toxin F) is a protein neurotoxin of the bungarotoxin family that is found in the venom of the many-banded krait, a snake found in Taiwan. Kappa-bungarotoxin is a high affinity antagonist of nicotinic acetylcholine receptors (nAChRs), particularly of CHRNA3; it causes a post-synaptic blockade of neurotransmission. Although there is significant variability in the clinical effects of snake bites, neuromuscular paralysis and respiratory failure are associated with krait bites.

Kappa-bungarotoxin was first reported in 1983 as a component of the venom of Bungarus multicinctus that differed in biological effect from the previously known alpha-bungarotoxin: Kappa, but not alpha, was capable of impeding nicotinic signaling in the chickciliary ganglion. The newly discovered toxin was designated "kappa" as an allusion to the Latin word kiliaris ("from the eye"), also the root of "ciliary". Separately identified toxins designated "toxin F" and "bungarotoxin 3.1" were identified by protein sequencing as identical to kappa-bungarotoxin.