Purification and subunit structure of a putative K+-channel protein identified by its binding properties for dendrotoxin I.
The binding protein for the K+-channel toxin dendrotoxin I was purified from a detergent extract of rat brain membranes. The purification procedure utilized chromatography on DEAE-Trisacryl, affinity chromatography on a dendrotoxin-I-Aca 22 column, and wheat germ agglutinin-Affigel 10 with a final 3800- to 4600-fold enrichment and a recovery of 8-16%. The high affinity (Kd, 40-100 pM) and specificity of the binding site are retained throughout the purification procedure. Analysis of the purified material on silver-stained NaDodSO4/polyacrylamide gel revealed three bands of Mr 76,000-80,000, 38,000, and 35,000. Interestingly, the binding site for 125I-labeled mast cell degranulating peptide, another putative K+-channel ligand from bee venom, which induces long-term potentiation in hippocampus, seems to reside on the same protein complex, as both binding sites copurify through the entire purification protocol.
Rehm
H
H
Centre de Biochimie du Centre National de la Recherche Scientifique, Nice, France.
Lazdunski
M
M
D000818:Animals; D001665:Binding Sites; D001923:Brain Chemistry; D002845:Chromatography; D004546:Elapid Venoms / Q000378:metabolism*; D007473:Ion Channels / Q000032:analysis*; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000302:isolation & purification* / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D051381:Rats
D004546:Elapid Venoms; D007473:Ion Channels; D009419:Nerve Tissue Proteins; D010455:Peptides; C008331:mast cell degranulating peptide; C020273:dendrotoxin