1kcp
From Proteopedia
3D STRUCTURE OF K-CONOTOXIN PVIIA, A NOVEL POTASSIUM CHANNEL-BLOCKING TOXIN FROM CONE SNAILS, NMR, 22 STRUCTURES
Structural highlights
FunctionO17A_CONPU Kappa-conotoxins bind and inhibit voltage-gated potassium channels (Kv). This toxin inhibits the drosophila Shaker channel (IC(50)=57-80 nM) (PubMed:12074021, PubMed:10818087, PubMed:27093300). In vivo, when tested in fish, this toxin induces hyperactivity, followed by continuous contraction and extension of major fins, without immobilization or death (PubMed:9417043, PubMed:12074021). Injection of this peptide together with the delta-conotoxin PVIA causes the sudden tetanus of prey (STOP) syndrome, which is a single, lethal 'fin-pop' in envenomed fish (PubMed:9417043, PubMed:12074021). When tested in mice, induces hyperactivity (PubMed:9417043).[1] [2] [3] [4] [5] [6] Publication Abstract from PubMedkappa-Conotoxin PVIIA from the venom of Conus purpurascens is the first cone snail toxin that was described to block potassium channels. We synthesized chemically this toxin and showed that its disulfide bridge pattern is similar to those of omega- and delta-conotoxins. kappa-conotoxin competes with radioactive alpha-dendrotoxin for binding to rat brain synaptosomes, confirming its capacity to bind to potassium channels; however, it behaves as a weak competitor. The three-dimensional structure of kappa-conotoxin PVIIA, as elucidated by NMR spectroscopy and molecular modeling, comprises two large parallel loops stabilized by a triple-stranded antiparallel beta-sheet and three disulfide bridges. The overall fold of kappa-conotoxin is similar to that of calcium channel-blocking omega-conotoxins but differs from those of potassium channel-blocking toxins from sea anemones, scorpions, and snakes. Local topographies of kappa-conotoxin PVIIA that might account for its capacity to recognize Kv1-type potassium channels are discussed. Three-dimensional structure of kappa-conotoxin PVIIA, a novel potassium channel-blocking toxin from cone snails.,Savarin P, Guenneugues M, Gilquin B, Lamthanh H, Gasparini S, Zinn-Justin S, Menez A Biochemistry. 1998 Apr 21;37(16):5407-16. PMID:9548922[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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