WLIP and tolaasin I, lipodepsipeptides from Pseudomonas reactans and Pseudomonas tolaasii, permeabilise model membranes.
The activity of the White Line Inducing Principle (WLIP) and tolaasin I, produced by virulent strains of Pseudomonas reactans and Pseudomonas tolaasii, respectively, was comparatively evaluated on lipid membranes. Both lipodepsipeptides were able to induce the release of calcein from large unilamellar vesicles. Their activity was dependent on the toxin concentration and liposome composition and in particular it increased with the sphingomyelin content of the membrane. Studies of dynamic light scattering suggested a detergent-like activity for WLIP at high concentration (> 27 microM). This effect was not detected for tolaasin I at the concentrations tested (< 28 microM). Differences were also observed in lipodepsipeptides secondary structure. In particular, the conformation of the smaller WLIP changed slightly when it passed from the buffer solution to the lipid environment. On the contrary, we observed a valuable increment in the helical content of tolaasin I which was inserted in the membrane core and oriented parallel to the lipid acyl chains.
Coraiola
M
M
ITC-CNR Istituto di Biofisica, via Sommarive 18, I-38050 Povo (Trento), Italy. manucora@itc.it
Lo Cantore
P
P
Lazzaroni
S
S
Evidente
A
A
Iacobellis
N S
NS
Dalla Serra
M
M
D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000302:isolation & purification / Q000494:pharmacology; D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000302:isolation & purification / Q000494:pharmacology*; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D047630:Depsipeptides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008070:Lipopolysaccharides / Q000737:chemistry / Q000378:metabolism; D008074:Lipoproteins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D008563:Membrane Lipids / Q000737:chemistry / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008954:Models, Biological; D008969:Molecular Sequence Data; D010539:Permeability / Q000187:drug effects*; D011549:Pseudomonas / Q000737:chemistry*
D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D047630:Depsipeptides; D008070:Lipopolysaccharides; D008074:Lipoproteins; D008563:Membrane Lipids; C023023:lipid-linked oligosaccharides; C067241:tolaasin protein, Pseudomonas tolaasii