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WLIP and tolaasin I, lipodepsipeptides from Pseudomonas reactans and Pseudomonas tolaasii, permeabilise model

M Coraiola1, P Lo Cantore, S Lazzaroni

  • 1ITC-CNR Istituto di Biofisica, via Sommarive 18, I-38050 Povo (Trento), Italy. manucora@itc.it

Biochimica Et Biophysica Acta
|August 24, 2006
PubMed

Insights

White Line Inducing Principle (WLIP) and tolaasin I toxins both disrupt lipid membranes, with activity influenced by sphingomyelin content. WLIP exhibits detergent-like effects at high concentrations, unlike tolaasin I.

Area of Science:

  • Biochemistry
  • Membrane Biophysics
  • Microbial Toxinology

Background:

  • Pseudomonas reactans and Pseudomonas tolaasii produce virulent lipodepsipeptides.
  • White Line Inducing Principle (WLIP) and tolaasin I are key toxins studied for their membrane interactions.

Purpose of the Study:

  • To comparatively evaluate the activity of WLIP and tolaasin I on lipid membranes.
  • To investigate the influence of liposome composition and toxin concentration on membrane disruption.

Main Methods:

  • Large unilamellar vesicles (LUVs) were used to assess calcein release.
  • Dynamic light scattering (DLS) was employed to study toxin-induced membrane changes.
  • Spectroscopic methods were utilized to analyze secondary structures of the lipodepsipeptides.

Main Results:

  • Both WLIP and tolaasin I induced calcein release from LUVs in a concentration-dependent manner.
  • Membrane sphingomyelin content significantly enhanced the activity of both toxins.
  • WLIP displayed detergent-like activity at >27 microM, while tolaasin I did not at <28 microM.
  • Conformational changes were observed for both toxins upon interaction with lipid membranes, with tolaasin I showing increased helical content.

Conclusions:

  • WLIP and tolaasin I exhibit distinct mechanisms of membrane interaction and structural responses.
  • Lipid membrane composition, particularly sphingomyelin, plays a crucial role in modulating toxin activity.
  • Understanding these differences is vital for elucidating bacterial pathogenesis and developing targeted interventions.

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