A novel Flavobacterium quisquiliarum porphyrin binding protein independently disrupts Pseudomonas aeruginosa biofilms

Bacterial biofilms underpin chronic infection and antimicrobial resistance, notably in Pseudomonas aeruginosa . Here we deconvolute a commercial alginate lyase preparation from Flavobacterium quisquiliarum and identify a previously uncharacterised ~ 21 kDa porphyrin-binding protein ( Fq PBP). Structural, biophysical and docking analyses reveal high-affinity tetrapyrrole binding. Recombinant Fq PBP independently inhibits and disperses P. aeruginosa biofilms, implicating porphyrin sequestration and iron homeostasis in biofilm control and highlighting a potential therapeutic strategy targeting iron acquisition pathways. Data are available via ProteomeXchange with identifier PXD081358.