Intimations of K+ channel structure from a complete functional map of the molecular surface of charybdotoxin.
The external vestibules of many K+ channels carry a high-affinity receptor for charybdotoxin, a peptide of known structure. Point mutations of a recombinant toxin identified the residues directly involved in the interaction with a Ca(2+)-activated K+ channel. The interaction surface is formed from 8 of the 37 residues and covers about 25% of the peptide's molecular surface. The shape of the toxin permits a deduced picture of the complementary receptor site in the external vestibule of the K+ channel.
Stampe
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Howard Hughes Medical Institute, Graduate Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02254-9110.
Kolmakova-Partensky
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Miller
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C
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000494:pharmacology; D018999:Charybdotoxin; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D017354:Point Mutation; D015221:Potassium Channels / Q000737:chemistry* / Q000378:metabolism; D017510:Protein Folding; D017433:Protein Structure, Secondary; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry; D012604:Scorpion Venoms / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D015221:Potassium Channels; D011994:Recombinant Proteins; D012604:Scorpion Venoms; D018999:Charybdotoxin; D002118:Calcium