Murein transglycosylase from phage lambda lysate. Purification and properties

Area of Science:

• Microbiology
• Molecular Biology
• Enzymology

Background:

• Bacteriophage lambda infection involves lysis of the host bacterium, E. coli.
• Bacterial lysates contain enzymes that degrade the cell wall (murein).
• Two key enzymes, endopeptidase and murein transglycosylase, are present in induced E. coli (lambda) lysogens.

Purpose of the Study:

• To isolate and characterize the murein transglycosylase from E. coli (lambda) lysogens.
• To compare its properties and activity with known enzymes.
• To determine if this enzyme is the phage lambda R-gene product.

Main Methods:

• Enzyme purification from induced E. coli (lambda) lysogen lysates.
• Biochemical characterization of the purified murein transglycosylase.
• Assay of bacteriolytic activity and comparison with hen egg lysozyme.

Main Results:

• Murein transglycosylase was successfully separated from endopeptidase and purified to homogeneity.
• The purified enzyme displayed a 200-fold higher bacteriolytic activity compared to hen egg lysozyme.
• The enzyme's properties (MW 17,500, pH optimum 6.6, Zn2+ inactivation) distinguish it from previously described bacterial enzymes.
• Endopeptidase alone did not lyse cells but enhanced lysis extent.

Conclusions:

• The purified murein transglycosylase is a distinct enzyme with potent bacteriolytic capabilities.
• The data strongly suggest this enzyme is the product of the phage lambda R-gene.
• This finding contributes to understanding phage-mediated bacterial lysis mechanisms.