Fig. 7.

Summary of AHL quorum quenching strategies. (A) Three well-known AHL quorum-quenching strategies. Quenching of AHL signaling by inhibiting AHL synthesis (middle green arrow) or AHL-receptor binding (bottom green arrow) by small molecular chemicals or enzymatically degrading AHL (top green arrow) are indicated. (B) A proposed model of LqqP-mediated quenching of PcoI-dependent AHL signaling, representing a new quorum-quenching mechanism through protein–protein interaction. The direct binding of LqqP and PcoI reduces the abundance of free PcoI in E. coli through an unknown mechanism. LuxI and PcoI: AHL synthase, LuxR and PcoR: AHL receptor transcriptional regulator. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)