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Interaction between tetanolysin and Mycoplasma cell membrane
Biochimica Et Biophysica Acta
|December 14, 1976
Summary
Tetanolysin lyses sterol-requiring Mycoplasma capricolum cells by binding to membrane cholesterol. This interaction is inhibited by cholesterol and Mg2+, and affects membrane fluidity.
Area of Science:
- Microbiology
- Biochemistry
- Molecular Biology
Background:
- Mycoplasma species, such as Mycoplasma capricolum, require sterols for their cell membranes.
- Tetanolysin is a toxin produced by Clostridium tetani.
- Understanding the interaction between toxins and cell membranes is crucial for developing therapeutic strategies.
Purpose of the Study:
- To investigate the mechanism by which tetanolysin interacts with and lyses Mycoplasma capricolum cells.
- To identify the specific components of the mycoplasma membrane responsible for tetanolysin binding.
- To elucidate the effects of tetanolysin binding on membrane properties.
Main Methods:
- Cell lysis assays using Mycoplasma capricolum and Acholeplasma laidlawii.
- Hemolytic assays to quantify tetanolysin activity.
- Membrane isolation and binding studies.
- Pronase digestion of membrane proteins.
- Electron paramagnetic resonance (EPR) spectrometry.
Main Results:
- Tetanolysin specifically lysed sterol-requiring Mycoplasma capricolum but not sterol-non-requiring Acholeplasma laidlawii.
- Lysis was temperature-dependent and inhibited by cholesterol, Mg2+, and lucensomycin.
- Mycoplasma capricolum membranes bound significantly more tetanolysin than adapted strains, with binding dependent on membrane lipids, not proteins.
- Two tetanolysin polypeptides (44,000 and 42,000 Da) bound to mycoplasma membranes.
- Tetanolysin treatment increased membrane fluidity.
Conclusions:
- Tetanolysin specifically targets and binds to cholesterol in the Mycoplasma capricolum cell membrane.
- This interaction leads to cell lysis and alters membrane physical properties.
- The findings suggest a model where tetanolysin shields membrane cholesterol from phospholipids.
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