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Effect of phi X174 protein E-mediated lysis on murein composition of Escherichia coli
1Institute of Microbiology and Genetics, University of Vienna, Austria. emily@gem.univie.ac.at
Abstract:
Lysis of Escherichia coli by bacteriophage phi X174 is caused by the phage protein E. As protein E is devoid of enzymatic activities it has been postulated that lysis is the result of an induction of the autolytic enzymes of the host. This hypothesis was investigated by comparing the murein composition before and during lysis of either phi X174 infected cells or protein E induced lysis of E. coli. Additionally, protein E-mediated lysis was compared with induction of the autolytic system by EDTA. The analysis showed that the overall composition of murein is not changed after induction of protein E-mediated lysis. Nevertheless, murein degradation seems to be stimulated by the action of protein E as shown by an increase in the total amount of murein turnover products by about 10%. It could be shown that an intact murein sacculus prevents the phages from being released.
Insights
Bacteriophage phi X174 protein E induces lysis in Escherichia coli by stimulating murein degradation, not by altering murein composition. An intact murein sacculus is essential for preventing phage release.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Bacteriophage phi X174 protein E is responsible for lysis of Escherichia coli.
- Protein E lacks enzymatic activity, suggesting it induces host autolytic enzymes for lysis.
Purpose of the Study:
- To investigate the mechanism of lysis induced by bacteriophage phi X174 protein E.
- To determine if protein E alters murein composition or stimulates autolytic enzymes.
Main Methods:
- Comparing murein composition in phi X174 infected E. coli and protein E-induced lysis.
- Analyzing murein turnover products after protein E induction.
- Comparing protein E-mediated lysis with EDTA-induced autolysis.
Main Results:
- Overall murein composition remained unchanged during protein E-mediated lysis.
- Murein degradation was stimulated by approximately 10% in terms of turnover products.
- An intact murein sacculus was found to prevent phage release.
Conclusions:
- Bacteriophage phi X174 protein E induces lysis by stimulating murein degradation, not by altering murein composition.
- The integrity of the murein sacculus is critical for phage progeny release.