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Oligomerization of Clostridium perfringens epsilon-toxin is dependent upon membrane fluidity in liposomes

Masahiro Nagahama1, Hideki Hara, Mariano Fernandez-Miyakawa

  • 1Department of Microbiology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770-8514, Japan.

Biochemistry
|January 4, 2006
PubMed

Insights

Clostridium perfringens epsilon-toxin oligomerization depends on membrane fluidity. Lowering the phase-transition temperature (Tm) of liposomes enhances toxin binding, insertion, and pore formation, crucial for its mechanism of action.

Area of Science:

  • Microbiology
  • Biochemistry
  • Membrane Biophysics

Background:

  • Clostridium perfringens epsilon-toxin is a pore-forming toxin.
  • Toxin oligomerization is essential for its membrane activity.
  • The role of membrane properties in epsilon-toxin function is not fully understood.

Purpose of the Study:

  • To investigate the mechanism of epsilon-toxin oligomerization.
  • To determine the influence of membrane fluidity on toxin-membrane interactions.
  • To elucidate how membrane phase-transition temperature affects toxin binding and pore formation.

Main Methods:

  • Carboxyfluorescein (CF)-loaded liposomes composed of various phosphatidylcholines (PCs) were used.
  • Toxin-induced CF leakage and toxin binding to liposomes were measured.
  • Surface plasmon resonance (SPR) with BIAcore and [125I]TID labeling were employed.

Main Results:

  • Decreased phase-transition temperature (Tm) of PCs increased CF leakage, toxin binding, and functional oligomer formation.
  • SPR confirmed increased toxin binding with decreased Tm.
  • [125I]TID labeling showed toxin insertion into the hydrophobic membrane region.

Conclusions:

  • Membrane fluidity significantly impacts epsilon-toxin binding and insertion into liposomes.
  • Lipid composition, specifically Tm, is critical for epsilon-toxin oligomerization and membrane damage.
  • Understanding these interactions is key to developing strategies against epsilon-toxin toxicity.

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