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Functioning of the cloned phage MS2 lysis protein in Escherichia coli impaired in murein synthesis
A Ursinus-Wössner1, J V Höltje
1Max-Planck-Institut für Entwicklungsbiologie, Abteilung Biochemie, Tübingen, F.R.G.
Abstract:
The mode of action of the phage MS2 lysis protein seems not to involve a direct interaction with the murein synthesis machinery as is the case for lysis induced by beta-lactam antibiotics. Mutants with defects in various penicillin-binding proteins, which are involved in murein synthesis, were found to show normal lysis sensitivity towards the cloned MS2 lysis protein. In addition, both processes, longitudinal growth of the murein sacculus in the presence of furazlocillin, cephalexin and nalidixic acid as well as spherical growth in the presence of mecillinam were sensitive to the phage lysis protein. No change in the capacity of the binding proteins to bind 14C-labelled penicillin G was observed in the presence of the MS2 lysis gene product.
Insights
Bacteriophage MS2 lysis protein does not target murein synthesis machinery. Studies show it affects cell wall growth even when penicillin-binding proteins are defective, indicating a distinct lysis mechanism.
Area of Science:
- Bacteriophage biology
- Bacterial cell wall synthesis
- Molecular mechanisms of lysis
Background:
- Bacteriophage lysis is crucial for viral replication and release.
- Beta-lactam antibiotics induce bacterial lysis by inhibiting murein synthesis.
- The precise mechanism of MS2 phage lysis protein remains incompletely understood.
Purpose of the Study:
- To investigate the mode of action of the bacteriophage MS2 lysis protein.
- To determine if MS2 lysis protein directly interacts with bacterial murein synthesis pathways.
- To compare the lysis mechanism of MS2 protein with that of beta-lactam antibiotics.
Main Methods:
- Utilized mutants with defects in penicillin-binding proteins (PBPs) involved in murein synthesis.
- Assessed lysis sensitivity of these mutants to cloned MS2 lysis protein.
- Examined the effect of MS2 lysis protein on bacterial cell wall growth under various antibiotic conditions (furazlocillin, cephalexin, nalidixic acid, mecillinam).
- Measured the binding capacity of PBPs to penicillin G in the presence of MS2 lysis gene product.
Main Results:
- Mutants with defective PBPs showed normal sensitivity to MS2 lysis protein, suggesting no direct interaction with murein synthesis machinery.
- MS2 lysis protein inhibited both longitudinal and spherical bacterial cell wall growth in the presence of different antibiotics.
- The MS2 lysis gene product did not alter the penicillin-binding capacity of PBPs.
Conclusions:
- The bacteriophage MS2 lysis protein operates via a mechanism distinct from beta-lactam antibiotics.
- MS2 lysis protein does not directly target or interfere with the bacterial murein synthesis machinery.
- The study provides evidence for an alternative pathway for phage-induced bacterial lysis.