A cytolytic δ‐endotoxin from Bacillus thuringiensis var. israelensis forms cation‐selective channels in planar lipid bilayers

FEBS Letters

Blatt, Michael R.²  Knowles, Barbara H.³  Carroll, Joe³  Ellar, David J.³  Menestrina, Gianfranco¹  Tester, Mark²  Horsnell, Jane M.³ 

[1] Dipartimento di Fisica, Universitá di Trento, I-38050 Povo, Italy;Department of Botany, University of Cambridge, Downing Street, Cambridge CB2 3EA, England;Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW England

关键词: Endotoxin;    δ-;    Ion channel;    Planar lipid bilayer;    (Bacillus thuringiensis var. israelensis);   

DOI  :  10.1016/0014-5793(89)80540-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

In order to determine the mechanism of action of the 27 kDa mosquitocidal δ-endotoxin of Bacillus thuringiensis var. israelensis we have studied its effects on the conductance of planar lipid bilayers. The toxin formed cation-selective channels in the bilayers, permeable to K⁺ and Na⁺ but not to N-methylglucamine or Cl⁻, showing very fast, cooperative opening and closing. Channel opening was greatly reduced in the presence of divalent cations (Ca²⁺, Mg²⁺) and the effect was reversed when these ions were removed. These results are consistent with our proposal that B. thuringiensis toxins act by a mechanism of colloid-osmotic lysis.

【 授权许可】

Unknown