Purification of binding protein for Tityus gamma toxin identified with the gating component of the voltage-sensitive Na+ channel.
The gating component associated with the voltage-sensitive Na+ channel from electroplax membranes of Electrophorus electricus has been purified by using toxin gamma from the venom of the scorpion Tityus serrulatus serrulatus. The toxin-binding site was efficiently solubilized with Lubrol PX, resulting in an extract of high initial specific activity. Purification was achieved by adsorption of the toxin-binding component to DEAE-Sephadex A-25 followed by desorption at high ionic strength and chromatography on either wheat germ agglutinin-Ultrogel or Sepharose 6B. Maximal final specific activities were at least 42% of the specific activity expected for a pure toxin-binding component. The purified material exhibited a Stokes radius of 85 A, and sodium dodecyl sulfate/polyacrylamide gel electrophoresis demonstrated a single polypeptide component of Mr 270,000. Furthermore, tetrodotoxin binding activity and Tityus gamma toxin binding activity copurified, suggesting that the selectivity filter and the gating component of the Na+ channel are carried by the same polypeptide chain.
D000818:Animals; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D004557:Electric Organ / Q000378:metabolism*; D004593:Electrophorus; D007473:Ion Channels / Q000378:metabolism*; D007700:Kinetics; D009498:Neurotoxins / Q000378:metabolism*; D011950:Receptors, Cholinergic / Q000378:metabolism*; D012604:Scorpion Venoms / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D015222:Sodium Channels
D002352:Carrier Proteins; D007473:Ion Channels; D009498:Neurotoxins; D011950:Receptors, Cholinergic; D012604:Scorpion Venoms; D015222:Sodium Channels; C029574:scorpion toxin receptor; C023790:tetrodotoxin-binding protein; C003609:tityustoxin; D012964:Sodium