N-(β-ketocaproyl)-L-Homoserine lactone

N-(β-ketocaproyl)-L-Homoserine lactone (CAS No.: 143537-62-6) is a prototypical N-acyl homoserine lactone (AHL) autoinducer that functions as a key signaling molecule in quorum sensing systems of Gram-negative bacteria, where it mediates cell density–dependent regulation of gene expression. Endogenously synthesized by LuxI-type enzymes from S-adenosylmethionine and acyl carrier protein substrates, this molecule diffuses across bacterial membranes and binds intracellular LuxR-family transcriptional regulators, promoting receptor multimerization and enhanced DNA binding to target promoter regions. Through this mechanism, it modulates diverse biological processes including biofilm formation, virulence factor production, and secondary metabolite biosynthesis, notably activating transcriptional programs such as carbapenem antibiotic production via CarR in certain species, with reported binding activity in the low micromolar range. As a well-characterized quorum sensing agonist, it is extensively employed in studies of microbial communication, host–pathogen interactions, and regulatory networks in organisms such as Erwinia carotovora and Yersinia enterocolitica. In biomedical research and drug discovery, it serves as a valuable tool compound for dissecting LuxR-type signaling pathways, evaluating quorum sensing inhibitors, and exploring anti-virulence therapeutic strategies, with experimental concentrations typically adjusted according to specific cellular systems and assay designs.