Wall Teichoic Acids Are Direct Molecular Targets of Antimicrobial Peptides in Gram-Positive Bacteria

Lytic antimicrobial peptides (AMPs) are long recognized for their ability to disrupt bacterial membranes, yet their interactions with other cell-envelope components remain poorly understood. Such knowledge is essential for redesigning AMPs as next-generation antibiotics or tailoring them for strain-specific activity. Here we show, using solid-state and solution NMR, that cationic AMPs engage directly with wall teichoic acids (WTAs)─anionic polymers in the Gram-positive bacteria cell wall. Three representative AMPs acting through different mode of membrane disruption display distinct binding to WTA phosphate groups. Solution NMR of purified WTAs further reveals peptide polymer interactions as well as the residues responsible for recognition. These findings broaden the classical view of AMP action beyond membrane permeabilization, highlighting WTAs as key molecular targets and paving the way for the rational design of peptide antibiotics with tailored specificity.