Characterization of a potassium channel toxin from the Caribbean Sea anemone Stichodactyla helianthus.
A peptide toxin, ShK, that blocks voltage-dependent potassium channels was isolated from the whole body extract of the Caribbean sea anemone Stichodactyla helianthus. It competes with dendrotoxin I and alpha-dendrotoxin for binding to synaptosomal membranes of rat brain, facilities acetylcholine release at an avian neuromuscular junction and suppresses K+ currents in rat dorsal root ganglion neurones in culture. Its amino acid sequence is R1SCIDTIPKS10RCTAFQCKHS20MKYRLSFCRK30TCGTC35. There is no homology with other K+ channel-blocking peptides, except for BgK from the sea anemone Bunodosoma granulifera. ShK and BgK appear to be in a different structural class from other toxins affecting K+ channels.
Castañeda
O
O
Facultad de Biología, Universidad de La Habana, Cuba.
Sotolongo
V
V
Amor
A M
AM
Stöcklin
R
R
Anderson
A J
AJ
Harvey
A L
AL
Engström
A
A
Wernstedt
C
C
Karlsson
E
E
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D003064:Cnidarian Venoms / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D008969:Molecular Sequence Data; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000032:analysis; D051381:Rats; D012615:Sea Anemones / Q000737:chemistry*; D013574:Synaptosomes / Q000378:metabolism
D000596:Amino Acids; D003064:Cnidarian Venoms; D026902:Potassium Channel Blockers; D015221:Potassium Channels; C095391:ShK neurotoxin