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Protein and fatty acid composition of mesosomal vesicles and plasma membranes of Staphylococcus aureus
Abstract:
Qualitatively, the protein and fatty acid composition of purified mesosomal vesicles and the plasma membrane isolated from Staphylococcus aureus ATCC 6538P are identical, the major difference between these two cellular components being only quantitative in nature. Mesosomal vesicles and plasma membranes, when subjected to acidic or neutral disk gel electrophoresis, exhibited more than 22 bands of protein. With urea-acetic acid gels, the plasma membrane had a higher concentration of "slower-migrating proteins" whereas "faster-migrating proteins" predominated in the mesosomal vesicles. With neutral disk gel electrophoresis, mesosomal vesicles exhibited one prominent protein band with an approximate molecular weight of 35,000 and which was four times greater than that found in the corresponding region on gels of the plasma membrane. Finally, fatty acid analyses by capillary column gas chromatography showed that although the fatty acid composition is the same, the fatty acid content in mesosomal vesicles is 48% greater than that of the plasma membrane. The dominant fatty acids in both of these cellular components are the iso and anteiso branched methyl C15, C17, and C19 fatty acids and comprise at least 85% of the total fatty acids extracted. These results show that distinct chemical differences exist between the mesosomal vesicles and the plasma membrane of Staphylococcus aureus.
Insights
The protein and fatty acid composition of Staphylococcus aureus mesosomal vesicles and plasma membranes are qualitatively identical but quantitatively different. Mesosomal vesicles have a higher protein and fatty acid content than plasma membranes.
Area of Science:
- Microbiology
- Cell Biology
- Biochemistry
Background:
- Mesosomal vesicles and plasma membranes are critical cellular components in bacteria.
- Understanding their distinct biochemical properties is essential for comprehending bacterial physiology and pathogenesis.
- Staphylococcus aureus is a significant human pathogen, making its cellular structures a key area of research.
Purpose of the Study:
- To compare the protein and fatty acid composition of mesosomal vesicles and plasma membranes from Staphylococcus aureus ATCC 6538P.
- To identify qualitative and quantitative differences between these two cellular structures.
Main Methods:
- Purification of mesosomal vesicles and plasma membranes from Staphylococcus aureus.
- Analysis of protein composition using acidic, neutral, and urea-acetic acid disk gel electrophoresis.
- Determination of fatty acid composition and content using capillary column gas chromatography.
Main Results:
- Qualitatively identical protein and fatty acid profiles were observed between mesosomal vesicles and plasma membranes.
- Quantitative differences were noted: mesosomal vesicles showed a higher concentration of "faster-migrating proteins" and 48% greater total fatty acid content.
- Mesosomal vesicles exhibited a prominent protein band (approx. 35,000 MW) significantly more abundant than in plasma membranes.
Conclusions:
- Distinct chemical differences, primarily quantitative, exist between Staphylococcus aureus mesosomal vesicles and plasma membranes.
- These quantitative variations in protein and fatty acid content may reflect functional specializations of each cellular component.
- Further research is warranted to elucidate the functional implications of these biochemical disparities.