Phage peptide promotes bacterial cell death via inner and outer membrane targets

gp28, a 56-aa cationic peptide encoded by the T7-like coliphage phiKT, disrupts both inner and outer bacterial membranes and induces permeability changes linked to cell death.

• Why it matters: Phage-encoded CAMPs and how they drive bacterial lysis are less understood than mammalian peptides, limiting mechanistic insight and antimicrobial development.
• What they did: The study used biochemical fractionation to map gp28’s asymmetric membrane distribution, synthetic gp28 to measure inner-membrane permeability, and competition assays showing activity blocked by lipopolysaccharide and divalent cations.
• The result: gp28 shows surface charge-dependent activity against Gram-positive bacteria and broad bacteriostatic activity against multiple Gram-negative species, including clinical Uropathogenic Escherichia coli isolates.

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