Microcin E492 forms ion channels in phospholipid bilayer membranes

FEBS Letters

Lagos, Rosalba¹  Monasterio, Octavio¹  Cecchi, Ximena¹  Wilkens, Marcela¹  Vergara, Cecilia¹ 

[1] Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile

关键词: Ion channel;    Lipid bilayer;    Microcin E492;    Antibiotic;    Klebsiella pneumoniae;   

DOI  :  10.1016/0014-5793(93)80096-D

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Microcin E492, a polypeptide antibiotic, has been shown to have an M _r, of 6,000 by urea-SDS-polyacrylamide gel electrophoresis of the fluorescently labelled compound. It is known that the bactericidal action of microcin involves a loss of the transmembrane potential. In this study we show that microcin forms cation-selective channels in planar phospholipid bilayers. The channels have two main conductance states the current-voltage curves of which rectify. The reversal potentials measured under biionic conditions indicate a permeability sequence of NH₄ ⁺ > K⁺ = Rb⁺ = Cs⁺ > Na⁺ = Li⁺ > Tris⁺. The results suggest that membrane potential dissipation induced by microcin is a consequence of the formation of pores in the bacterial membrane.

【 授权许可】

Unknown