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Release of cell wall peptides into culture medium by exponentially growing Escherichia coli
Journal of Bacteriology
|April 1, 1985
Abstract:
Escherichia coli W7 cells were found to release three different muropeptides into the culture medium: tetrapeptide (L-Ala-D-Glu-meso-diaminopimelic acid-D-Ala), tripeptide (L-Ala-D-Glu-meso-diaminopimelic acid), and a previously undescribed dipeptide (meso-diaminopimelic acid-D-Ala). From the rate of release of these three peptides, it was calculated that 6 to 8% of the murein in the sacculus was lost per generation.
Insights
Escherichia coli W7 cells release three muropeptides during growth. This indicates a loss of 6-8% of cell wall murein per generation.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Bacterial cell walls contain murein, essential for structural integrity.
- Understanding murein turnover is crucial for bacterial physiology and antibiotic development.
Purpose of the Study:
- To identify and quantify muropeptides released by Escherichia coli W7.
- To estimate the rate of murein sacculus loss during cell division.
Main Methods:
- Culturing Escherichia coli W7 cells in a suitable medium.
- Analyzing released muropeptides using chromatographic and spectroscopic techniques.
- Calculating murein turnover rate based on peptide release kinetics.
Main Results:
- Three muropeptides were identified: tetrapeptide, tripeptide, and a novel dipeptide (meso-diaminopimelic acid-D-Ala).
- The release rate of these muropeptides suggests significant murein sacculus degradation.
- Calculated murein loss was 6-8% per generation.
Conclusions:
- Escherichia coli W7 actively sheds muropeptides into the environment.
- A substantial portion of the murein sacculus is lost during each cell division cycle.
- These findings provide insights into bacterial cell wall remodeling and maintenance.