Pores formed in lipid bilayers and in native membranes by nodularin, a cyanobacterial toxin.
Nodularin (NODLN), a cyclic pentapeptide hepatotoxin from the cyanobacterium Nodularia spumigena, induces pores in bilayers of diphytanoyl lecithin (DPhL) and in locust muscle membrane. NODLN increases the surface pressure of a DPhL monolayer; except when the surface pressure of the monolayer is high when the toxin causes a reduction of this parameter. NODLN pores exhibit many open conductance states; the higher state probabilities increasing when the transmembrane pressure is increased. The results from these studies are discussed in terms of two models for a NODLN pore, a torroidal model and a barrel-stave model. The edge energy of the NODLN pore of 1.4 x 10(-12) J/m is determined.
Spassova
M
M
Biomolecular Layers Department, Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria.
Mellor
I R
IR
Petrov
A G
AG
Beattie
K A
KA
Codd
G A
GA
Vais
H
H
Usherwood
P N
PN
D000818:Animals; D001427:Bacterial Toxins / Q000494:pharmacology; D000458:Cyanobacteria; D005260:Female; D006110:Grasshoppers; D008051:Lipid Bilayers; D008387:Marine Toxins / Q000494:pharmacology; D008566:Membranes / Q000187:drug effects / Q000648:ultrastructure; D009132:Muscles / Q000187:drug effects / Q000648:ultrastructure; D010456:Peptides, Cyclic / Q000494:pharmacology*; D010713:Phosphatidylcholines / Q000378:metabolism*; D012680:Sensitivity and Specificity
D001427:Bacterial Toxins; D008051:Lipid Bilayers; D008387:Marine Toxins; D010456:Peptides, Cyclic; D010713:Phosphatidylcholines; C063998:nodularin; C021016:1,2-diphytanoylphosphatidylcholine