PMID:9671721

Citation	Li-Smerin, Y and Swartz, KJ (1998) Gating modifier toxins reveal a conserved structural motif in voltage-gated Ca2+ and K+ channels. Proc. Natl. Acad. Sci. U.S.A. 95:8585-9
Abstract	Protein toxins from venomous animals exhibit remarkably specific and selective interactions with a wide variety of ion channels. Hanatoxin and grammotoxin are two related protein toxins found in the venom of the Chilean Rose Tarantula, Phrixotrichus spatulata. Hanatoxin inhibits voltage-gated K+ channels and grammotoxin inhibits voltage-gated Ca2+ channels. Both toxins inhibit their respective channels by interfering with normal operation of the voltage-dependent gating mechanism. The sequence homology of hanatoxin and grammotoxin, as well as their similar mechanism of action, raises the possibility that they interact with the same region of voltage-gated Ca2+ and K+ channels. Here, we show that each toxin can interact with both voltage-gated Ca2+ and K+ channels and modify channel gating. Moreover, mutagenesis of voltage-gated K+ channels suggests that hanatoxin and grammotoxin recognize the same structural motif. We propose that these toxins recognize a voltage-sensing domain or module present in voltage-gated ion channels and that this domain has a highly conserved three-dimensional structure.
Links	PubMed PMC21119
Keywords	Amino Acid Sequence; Animals; Calcium Channels/chemistry; Calcium Channels/drug effects; Ion Channel Gating; Molecular Sequence Data; Peptides/chemistry; Peptides/pharmacology; Peptides, Cyclic/chemistry; Peptides, Cyclic/pharmacology; Potassium Channels/chemistry; Potassium Channels/drug effects; Sequence Homology, Amino Acid; Xenopus laevis
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
GRARO:WGRTX		GO:0019870: potassium channel inhibitor activity	ECO:0000314:		F		Fig. 2	complete CACAO 4347
GRARO:WGRTX	enables	GO:0019870: potassium channel inhibitor activity	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete

References

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