AHL
Full name: acyl-homoserine lactones
These are small signalling molecules which are employed in "quorum sensing" systems.
Currently, the most well studied of these molecules is 3-oxohexanoyl-homoserine lactone 3OC6HSL, which binds to the transcriptional activator protein LuxR to alter transcriptional regulation of the Lux operon.
references:
- Collins, C.H. et al. Directed Evolution of V. Fischeri LuxR for increased acyl-HSL's. Molecular Microbiology. 2005. [http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2958.2004.04437.x Abstract]