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Cell wall receptor for bacteriophage Mu G(+)
Abstract:
The invertible G segment in phage Mu DNA controls the host range of the phage. Depending on the orientation of the G segment, two types of phage particles, G(+) and G(-), are produced which recognize different cell surface receptors. The receptor for Mu G(+) was located in the lipopolysaccharide (LPS) of gram-negative bacteria. The analysis of different LPS core types and of mutants that were made resistant to Mu G(+) shows that the primary receptor site on Escherichia coli K-12 lies in the GlcNAc beta 1 . . . 6Glc alpha 1-2Glc alpha 1-part at the outer end of the LPS. Mu shares this receptor site in E. coli K-12 with the unrelated single-stranded DNA phage St-1. Phage D108, which is related to Mu, and phages P1 and P7, which are unrelated to Mu but contain a homologous invertible DNA segment, have different receptor requirements. Since they also bind to terminal glucose in a different configuration, they adsorb to and infect E. coli K-12 strains with an incomplete LPS core.
Insights
Bacteriophage Mu
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- The invertible G segment of bacteriophage Mu DNA dictates its host range.
- Phage particles (G(+) and G(-)) recognize distinct cell surface receptors based on G segment orientation.
Purpose of the Study:
- To identify the specific receptor for Mu G(+) on gram-negative bacteria.
- To elucidate the role of lipopolysaccharide (LPS) structure in phage Mu infection.
Main Methods:
- Analysis of various LPS core types in gram-negative bacteria.
- Characterization of bacterial mutants resistant to Mu G(+) infection.
Main Results:
- The primary receptor for Mu G(+) on Escherichia coli K-12 is located in the GlcNAc beta 1...6Glc alpha 1-2Glc alpha 1- moiety of the LPS.
- Phage St-1 shares this LPS receptor site with Mu G(+) in E. coli K-12.
- Related phage D108 and unrelated phages P1 and P7, despite having homologous invertible DNA segments, exhibit different receptor requirements and infect strains with incomplete LPS cores.
Conclusions:
- The terminal LPS structure is critical for Mu G(+) host specificity.
- Phage-LPS receptor interactions are diverse and can be shared or distinct among related and unrelated phages.