Cell wall receptor for bacteriophage Mu G(+)

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.