Mode of action of yeast killer toxins: channel formation in lipid bilayer membranes

Nature ◽  
1983 ◽  
Vol 302 (5910) ◽  
pp. 709-711 ◽  
Author(s):  
Bruce L. Kagan
Keyword(s):  
Lipid Bilayer ◽  
Mode Of Action ◽  
Channel Formation ◽  
Lipid Bilayer Membranes ◽  
Bilayer Membranes ◽  
Killer Toxins ◽  
Yeast Killer

scholarly journals Channel Formation by LktA of Mannheimia (Pasteurella) haemolytica in Lipid Bilayer Membranes and Comparison of Channel Properties with Other RTX-Cytolysins

Toxins ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 604 ◽  
Author(s):  
Roland Benz ◽  
Claudio Piselli ◽  
Andrew Potter
Keyword(s):  
Lipid Bilayer ◽  
Inflammatory Responses ◽  
Pasteurella Haemolytica ◽  
Target Cells ◽  
Theoretical Treatment ◽  
Channel Formation ◽  
Lipid Bilayer Membranes ◽  
Bilayer Membranes ◽  
Pathogenicity Factors ◽  
Rtx Toxins

Cytolysin LktA is one of the major pathogenicity factors of Mannheimia haemolytica (formerly Pasteurella haemolytica) that is the cause of pasteurellosis, also known as shipping fever pneumonia, causing substantial loss of sheep and cattle during transport. LktA belongs to the family of RTX-toxins (Repeats in ToXins) that are produced as pathogenicity factors by a variety of Gram-negative bacteria. Sublytic concentrations of LktA cause inflammatory responses of ovine leukocytes. Higher concentrations result in formation of transmembrane channels in target cells that may cause cell lysis and apoptosis. In this study we investigated channel formation by LktA in artificial lipid bilayer membranes made of different lipids. LktA purified from culture supernatants by polyethylene glycol 4000 precipitation and lyophilization had to be activated to frequently form channels by solution in 6 M urea. The LktA channels had a single-channel conductance of about 60 pS in 0.1 M KCl, which is about one tenth of the conductance of most RTX-toxins with the exception of adenylate cyclase toxin of Bordetella pertussis. The LktA channels are highly cation-selective caused by negative net charges. The theoretical treatment of the conductance of LktA as a function of the bulk aqueous concentration allowed a rough estimate of the channel diameter, which is around 1.5 nm. The size of the LktA channel is discussed with respect to channels formed by other RTX-toxins. We present here the first investigation of LktA in a reconstituted system.

Formation of asymmetrical planar lipid bilayer membranes from characterized monolayers

1983 ◽  
Vol 7 (4) ◽  
pp. 299-310 ◽  
Author(s):  
Pierre Tancrède ◽  
Paul Paquin ◽  
André Houle ◽  
Roger M. Leblanc
Keyword(s):  
Lipid Bilayer ◽  
Planar Lipid Bilayer ◽  
Lipid Bilayer Membranes ◽  
Bilayer Membranes
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