3OC12HSL

3OC12HSL, or N-(3-oxododecanoyl)-L-homoserine lactone (also written as 3OC12-HSL), is a signaling molecule in Gram-negative bacteria belonging to the acyl-homoserine lactone (AHL) family. It is best known as the primary autoinducer of the Las quorum-sensing system in Pseudomonas aeruginosa, where it coordinates group behaviors as cell density increases.

Chemically, 3OC12HSL consists of a homoserine lactone ring linked to a 12-carbon acyl side chain bearing a keto group at the third carbon. The molecule is diffusible and can cross cell membranes to regulate gene expression by binding the LasR transcriptional regulator, thereby modulating the transcriptional program of the cell.

Biological role in P. aeruginosa centers on LasI synthesizing 3OC12HSL, which, upon reaching a threshold concentration, binds LasR and activates the expression of numerous genes. These include virulence factors such as elastase and various proteases, as well as elements involved in biofilm formation and environmental adaptation. 3OC12HSL also interacts with the Rhl quorum-sensing system and can participate in interspecies signaling, influencing community behaviors beyond the producing organism.

In research and applied contexts, 3OC12HSL is a widely used model QS signal molecule. Detection and quantification methods include biosensor strains and analytical techniques like mass spectrometry. Because quorum sensing can regulate pathogenic traits, 3OC12HSL is a focal point for strategies aimed at disarming pathogens, such as quorum-sensing inhibitors and enzymatic quorum quenching, which seek to reduce virulence without promoting resistance.