N-octadecanoyl-L-Homoserine lactone

N-octadecanoyl-L-Homoserine lactone, sometimes called C18-HSL, is an N-acylated homoserine lactone (AHL). AHLs vary in acyl group length (C4-C18), in the substitution of C3 (hydrogen, hydroxyl, or oxo group), and in the presence or absence of one or more carbon-carbon double bonds in the fatty acid chain. These differences confer signal specificity through the affinity of transcriptional regulators of the LuxR family. N-octadecanoyl-L-Homoserine lactone is one of four lipophilic, long acyl side-chain bearing AHLs produced by the LuxI AHL synthase homolog SinI involved in quorum-sensing signaling in strains of Sinorhizobium meliloti. This and other hydrophobic AHLs tend to localize in relatively lipophilic cellular environments of bacteria and cannot diffuse freely through the cell membrane. The long-chain N-acylhomoserine lactones may be exported from cells by efflux pumps or may be transported between communicating cells by way of extracellular outer membrane vesicles.