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Low-molecular-weight substrate for the lysozyme of T4 bacteriophage
Abstract:
It has been shown that muropeptide CB, the chemically defined product of Escherichia coli B murein digestion by phage lambda endolysin, is the substrate for T4 lysozyme. This is the tetrasaccharide GlcNAc-MurNAc-GlcNAc-anMurNAc in which the carboxyl groups of MurNAc and anMurNAc residues are substituted by tetrapeptide LAla-DGlu-msA2pm-DAla (MurNAc = N-acetylmuramic acid, GlcNAc = N-acetyl-D-glucosamine, anMurNAc = 1,6-anhydro-N-acetylmuramic acid, LAla = L-alanine, DGlu = D-glutamic acid, msA2pm = meso-diaminopimelic acid). The substrate contains one bond hydrolysable by T4 lysozyme. The products of hydrolysis are the easily identifiable disaccharide muropeptides C6 (GlcNAc-MurNAc-LAla-DGlu-msA2pm-DAla) and CA (GlcNAc-anMurNac-LAla-DGlu-msA2pm-DAla). Thus the substrate may be used for the specific identification of murein N-acetylmuramoylhydrolases of the T4 lysozyme type, as well as for any quantitative measurement of the enzymatic reaction.
Insights
Muropeptide CB, derived from Escherichia coli B murein, acts as a specific substrate for T4 lysozyme. This tetrasaccharide allows for precise identification and quantification of T4-like murein N-acetylmuramoylhydrolases.
Area of Science:
- Microbiology
- Enzymology
- Structural Biology
Background:
- Escherichia coli B murein is a complex peptidoglycan structure.
- Phage lambda endolysin digestion yields muropeptide CB.
- T4 lysozyme is a well-characterized bacteriophage enzyme.
Purpose of the Study:
- To identify the specific substrate for T4 lysozyme.
- To characterize the hydrolysis products of muropeptide CB by T4 lysozyme.
- To establish a method for identifying and quantifying T4-like enzymes.
Main Methods:
- Chemical definition of muropeptide CB.
- Enzymatic digestion of muropeptide CB using T4 lysozyme.
- Analysis of hydrolysis products (disaccharide muropeptides C6 and CA).
Main Results:
- Muropeptide CB, a tetrasaccharide, is confirmed as the substrate for T4 lysozyme.
- T4 lysozyme specifically hydrolyzes one bond within muropeptide CB.
- Hydrolysis yields identifiable disaccharide muropeptides C6 and CA.
Conclusions:
- Muropeptide CB serves as a specific substrate for T4 lysozyme.
- This substrate enables the identification of T4-like murein N-acetylmuramoylhydrolases.
- The system allows for quantitative measurements of enzymatic activity.