New LsrK Ligands\nas AI‑2 Quorum Sensing Interfering\nCompounds against Biofilm Formation

Antimicrobial resistance (AMR) represents a critical\nglobal health\ncrisis. An innovative strategy to deal with AMR is to interfere with\nbiofilm formation and bacterial quorum sensing (QS). In this study,\nnewly designed autoinducer-2 (AI-2)-inspired compounds in targeting\nbiofilm-associated infections were evaluated for their ability to\ninhibit biofilm formation in Staphylococcus aureus and Pseudomonas aeruginosa. The most\neffective compounds, <b>5d</b>, <b>5e</b>, and <b>7b</b>, exhibited potent antibiofilm activity with minimal inhibitory concentrations\nin the low microgram per mL range. Detailed biological assays confirmed\nthat the antibiofilm activity was primarily driven through AI-2 QS\ninhibition rather than direct antimicrobial effects. The combination\nof different spectroscopic techniques, such as differential scanning\nfluorimetry, intrinsic tryptophan fluorescence, circular dichroism,\nand nuclear magnetic resonance, elucidated the binding between the\ncompounds and the LsrK enzyme, a key player in AI-2 mediated QS. Our\nfindings highlight the potential of these novel QS inhibitors as promising\ntherapeutic agents against biofilm-associated infections.