A symmetry-driven search for electrostatic interaction partners in charybdotoxin and a voltage-gated K+ channel.
A structural model of charybdotoxin bound to a Shaker K+ channel has emerged from mechanistic and mutagenic analysis of toxin-channel interactions. We test this model by predicting through-space electrostatic interactions between specific pairs of channel-toxin residues. Dissociation constants of channel-toxin variants, determined by radiolabeled toxin binding to Shaker-transfected COS membrane fragments, were used to identify pairs of residues located closely enough to interact electrostatically. The results further refine the structural model of the bound complex and produce a more detailed view of the vestibule of the Shaker channel.
Naini
A A
AA
Howard Hughes Medical Institute, Graduate Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02254-9110, USA.
Miller
C
C
D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D018999:Charybdotoxin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004563:Electrochemistry; D015640:Ion Channel Gating; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D015221:Potassium Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D051637:Shaker Superfamily of Potassium Channels; D013816:Thermodynamics; D014162:Transfection
D015221:Potassium Channels; D051637:Shaker Superfamily of Potassium Channels; D018999:Charybdotoxin