N-tetradecanoyl-L-homoserine lactone (C14-HSL) is a quorum sensing signaling molecule produced by certain Gram-negative bacteria, particularly those involved in biofilm formation, symbiosis, and pathogenic interactions. The biosynthesis of C14-HSL is catalyzed by acyl-homoserine lactone (AHL) synthase enzymes, commonly homologs of LuxI. This process begins with L-homoserine, which acts as the backbone for the molecule. The enzyme transfers a tetradecanoyl (C14) acyl group, derived from tetradecanoyl-CoA, to the amino group of L-homoserine, forming an amide bond. The intermediate product is then cyclized by the AHL synthase to form the lactone ring, producing N-tetradecanoyl-L-homoserine lactone (C14-HSL). Once synthesized, C14-HSL is secreted into the extracellular environment, where its concentration increases as the bacterial population grows. Upon reaching a critical threshold, C14-HSL binds to LuxR-type transcriptional regulators or their homologs, forming an active complex that induces the expression of quorum sensing-regulated genes. These genes control group behaviors such as biofilm maturation, secondary metabolite production, and adaptation to environmental changes, providing bacteria with a means of coordinating population-wide responses to their surroundings.

Quorum sensing: N-tetradecanoyl-L-homoserine lactone (C14-HSL) Biosynthesis References