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Bovine seminal ribonuclease destabilizes negatively charged membranes
J M Mancheño1, M Gasset, M Oñaderra
1Departamento de Bioquímica y Biología Molecular, Facultad de Química, Universidad Complutense, Madrid, Spain.
Abstract:
Bovine seminal ribonuclease (BS-RNase), an antitumor protein selectively cytotoxic for malignant cells, (i) specifically aggregates negatively charged vesicles and modifies the thermotropic behaviour of the phospholipid; (ii) decreases the amplitude of the thermal transition of the phospholipid; and (iii) provokes lipid-mixing between bilayers of negatively charged vesicles. This engenders leakage of the aqueous vesicle contents. Monomeric BS-RNase, devoid of antitumor action, does not produce these effects. These results suggest that the destabilization of the membrane bilayer promoted by BS-RNase may be involved in the antitumor action of the protein.
Insights
Bovine seminal ribonuclease (BS-RNase) selectively kills cancer cells by destabilizing their membranes. This antitumor protein aggregates vesicles and causes leakage, a process not seen with monomeric forms.
Area of Science:
- Biochemistry
- Molecular Biology
- Oncology
Background:
- Bovine seminal ribonuclease (BS-RNase) exhibits selective cytotoxicity against malignant cells.
- Understanding the mechanism of BS-RNase's antitumor activity is crucial for therapeutic development.
Purpose of the Study:
- To investigate the interaction of BS-RNase with lipid bilayers and its effect on membrane properties.
- To determine if BS-RNase-induced membrane destabilization contributes to its antitumor effects.
Main Methods:
- Studied the aggregation of negatively charged vesicles induced by BS-RNase.
- Analyzed modifications in phospholipid thermotropic behavior and thermal transition amplitude.
- Observed lipid-mixing between vesicle bilayers and leakage of vesicle contents.
Main Results:
- BS-RNase specifically aggregates negatively charged vesicles, altering phospholipid thermotropic behavior.
- The protein decreases the amplitude of phospholipid thermal transitions.
- BS-RNase induces lipid-mixing and leakage of aqueous contents from vesicle bilayers.
Conclusions:
- BS-RNase-induced destabilization of the membrane bilayer is a key factor in its antitumor activity.
- Monomeric BS-RNase, lacking antitumor effects, does not induce these membrane alterations.