About LL-37
LL-37 is the only human cathelicidin-derived peptide, released by proteolytic cleavage of the hCAP18 precursor encoded by the CAMP gene. The mature peptide is 37 residues long and begins with two leucines, which is where the name comes from. It adopts an amphipathic alpha-helix in the presence of anionic lipids — the structural feature most of its studied activity depends on.
Research on LL-37 falls into two broad strands. The first is direct membrane interaction: the cationic, amphipathic helix associates with anionic microbial membranes and is characterised for permeabilisation kinetics in vitro, and for binding and neutralising lipopolysaccharide (LPS). The second is receptor-mediated signalling, chiefly through the formyl peptide receptor FPR2/FPRL1, which is studied for chemotaxis and downstream innate immune pathway regulation.
Research Applications
LL-37 is used in research investigating host defence peptide structure-activity relationships, membrane permeabilisation and selectivity between microbial and mammalian lipid compositions, LPS binding and neutralisation assays, FPR2-mediated chemotaxis, and the regulation of innate immune signalling in cell models. It is also used as a reference peptide in comparative antimicrobial peptide work.