LL-37

LL-37 is a synthetic 37 amino acid cathelicidin antimicrobial peptide — the only cathelicidin expressed in humans — processed from the C-terminal domain of the hCAP18 precursor protein by extracellular proteinase 3. The sequence LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES adopts an amphipathic alpha-helical conformation in membrane-mimicking environments, with a net charge of approximately +6 at physiological pH that drives selective electrostatic attraction to negatively charged bacterial membrane phospholipids including phosphatidylglycerol and cardiolipin.

Molecular formula: C205H340N60O53S | Molecular weight: 4493.4 g/mol | CAS: 154947-66-7 | Sequence: LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES | Amino acids: 37 | Purity: greater than or equal to 98% as verified by HPLC | Form: Lyophilised powder | Appearance: White to off-white lyophilised powder | Storage: -20°C desiccated

Two primary models of LL-37 membrane disruption are studied using model membrane systems: the toroidal pore model (perpendicular insertion alongside lipid head groups forming water-filled pores) and the carpet model (parallel accumulation on the outer leaflet causing detergent-like solubilisation above a critical surface density). Researchers use solid-state NMR, oriented circular dichroism, and single-channel electrophysiology to distinguish between these mechanisms.

Beyond antimicrobial activity, LL-37 is studied as an immunomodulatory molecule via FPRL1 and P2X7 receptor engagement, dendritic cell maturation and T cell polarisation in immune cell models, and keratinocyte and fibroblast migration in wound healing assays. Zanetti (Journal of Leukocyte Biology, 2004) and Mookherjee and Hancock (Cell and Molecular Life Sciences, 2007) provide comprehensive mechanistic reviews.

Supplied as a lyophilised powder. Reconstitute in sterile water. Store at -20°C. For laboratory and analytical research purposes only. Not for human or veterinary use.