[Channel-forming activity at planar lipid bilayer of the membrane active polypeptide B form venom of Bungarus fasciatus].
Using planar lipid bilayer formed by lecithin and cholesterol (20 and 5 mg/ml respectively in N-decane) the channel-forming activity of the membrane active polypeptide B(BMAP B) from the venom of Bungarus fasciatus was investigated. Under the existence of a voltage or a salt concentration gradient between two sides of the bilayer, unit conductance fluctuation and a decrease in steady state resistance accompanying BMAP B incorporation and channel formation were observed. By measuring the reversal potential in an asymmetric solution, the selectivity of the BMAP B-channel was estimated having a value of PK/PC1 = 1.4. Divalent cations, such as Ba2+, Ca2+ inhibited the channel activity as they did in biomembranes. These data might provide an explanation for the depolarizing effect of the membrane active polypeptide on the native membranes.
Shi
Y L
YL
Shanghai Institute of physiology, Academia Sinica.
Wang
W P
WP
Zhang
H
H
Xu
K
K
D000818:Animals; D002038:Bungarotoxins / Q000737:chemistry*; D002413:Cations, Divalent; D002784:Cholesterol; D004179:Cobra Cardiotoxin Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D007473:Ion Channels; D008051:Lipid Bilayers; D010713:Phosphatidylcholines
D002038:Bungarotoxins; D002413:Cations, Divalent; D004179:Cobra Cardiotoxin Proteins; D007473:Ion Channels; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D002784:Cholesterol