N-Acyl-3-amino-5H-furanone derivatives as new inhibitors of LuxR-dependent quorum sensing: Synthesis, biological evaluation and binding mode study

New N-acyl homoserine lactone analogues, N-acyl-3-amino-5H-furanone derivatives and some 4-halogeno counterparts, were synthesised and tested for their ability to modulate LuxR-dependent bacterial quorum sensing. Both types of analogues proved to be inhibitors, the halogenated compounds being significantly more active. Molecular modelling suggested that the conjugated enamide group induces two preferential conformations leading to specific binding modes. In addition, the presence of the halogen atom could enhance the fitting of the lactone ring through specific interactions with strictly conserved or conservatively replaceable residues in the LuxR protein family, namely Asp79, Trp94 and Ile81.