LC-LL-37, with Cys in Nterm

Product Name: LC-LL-37, with Cys in Nterm

Sequence One Letter Code: C-LC-LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES

Sequence Three Letter Code: H-Cys-LC-Leu-Leu-Gly-Asp-Phe-Phe-Arg-Lys-Ser-Lys-Glu-Lys-Ile-Gly-Lys-Glu-Phe-Lys-Arg-Ile-Val-Gln-Arg-Ile-Lys-Asp-Phe-Leu-Arg-Asn-Leu-Val-Pro-Arg-Thr-Glu-Ser-OH

Molecular Weight: 4709.9

Purity: 95%

Form: Lyophilized

Storage Conditions: - 20 °C

Research Area: Infection Disease Research

Source / Species: human

Conjugation: Unconjugated

Code Nacres: NA.26

Application: LC-LL-37 is a modified form of the human antimicrobial peptide LL-37, a member of the cathelicidin family involved in innate immune defense. LL-37 adopts an amphipathic α-helical structure that disrupts microbial membranes and modulates immune responses at sites of infection. The inclusion of an N-terminal cysteine permits site-specific conjugation or immobilization without compromising biological activity. LC-LL-37 retains antimicrobial and immunomodulatory properties and is widely used in studies of host defense, inflammation, wound healing, and peptide-based therapeutic development. It is also suitable for biomaterial functionalization and mechanistic investigations of membrane disruption.

Current Research: Antimicrobial peptides (AMPs) are essential components of the innate immune system that protect the host against microbial infection. Among the best-characterized human AMPs is LL-37, the only member of the cathelicidin family found in humans. This peptide exhibits broad antimicrobial activity and plays important roles in immune regulation, inflammation, and tissue repair. LC-LL-37 is a modified form of LL-37 that includes an N-terminal cysteine residue, enabling site-specific conjugation and surface immobilization while preserving the peptide’s biological functions. This modification expands the experimental versatility of LL-37 in biochemical, cellular, and biomaterials research. LL-37 and the Human Cathelicidin Family LL-37 is derived from the precursor protein human cationic antimicrobial protein 18 (hCAP18) through proteolytic cleavage. The resulting 37-amino-acid peptide begins with two leucine residues, which gives rise to the name LL-37. As part of the innate immune system, LL-37 is expressed by several cell types including epithelial cells, neutrophils, macrophages, and keratinocytes. It is released in response to microbial invasion or inflammatory signals and accumulates at sites of infection. Beyond its direct antimicrobial effects, LL-37 participates in immune signaling, modulation of inflammatory responses, and regulation of wound healing, highlighting its multifunctional role in host defense. Structural Features and Membrane Interaction LL-37 adopts an amphipathic α-helical structure, meaning that one side of the helix contains hydrophobic residues while the opposite side contains positively charged residues. This structural arrangement allows the peptide to interact strongly with negatively charged microbial membranes. When LL-37 encounters bacterial membranes, electrostatic interactions attract the peptide to the cell surface. The peptide then inserts into the lipid bilayer, destabilizing membrane integrity. This disruption can lead to membrane permeabilization, leakage of cellular contents, and eventual microbial cell death. Because microbial membranes differ in composition from mammalian membranes, LL-37 preferentially targets pathogens while maintaining relatively low toxicity toward host cells. Immunomodulatory Functions In addition to its antimicrobial activity, LL-37 functions as an immunomodulatory peptide that influences multiple aspects of immune signaling. It can recruit immune cells such as neutrophils, monocytes, and T cells to sites of infection through chemotactic signaling. LL-37 also modulates cytokine production and can regulate inflammatory responses by interacting with pattern recognition receptors and other signaling pathways. Through these mechanisms, the peptide contributes to the coordination of innate and adaptive immune responses. These immunomodulatory properties have made LL-37 a subject of significant interest in studies of host defense and inflammatory regulation. Design and Features of LC-LL-37 LC-LL-37 is a modified version of LL-37 that contains an additional cysteine residue at the N-terminus. The thiol group of cysteine provides a reactive site that can be used for chemical conjugation or immobilization without altering the core sequence of the peptide. This modification allows researchers to attach LC-LL-37 to a variety of surfaces or molecules through thiol-specific coupling reactions, such as maleimide chemistry or disulfide bond formation. Importantly, the N-terminal cysteine is positioned so that it does not interfere with the peptide’s amphipathic helix or its ability to interact with microbial membranes. As a result, LC-LL-37 retains the antimicrobial and immunomodulatory functions of the native peptide. Applications in Antimicrobial Research LC-LL-37 is widely used in antimicrobial activity studies, where researchers investigate how peptides disrupt microbial membranes and inhibit bacterial growth. The peptide can be applied in assays evaluating activity against a range of pathogens, including Gram-positive bacteria, Gram-negative bacteria, and certain fungi. Because the peptide can be immobilized on surfaces through its cysteine residue, it is particularly useful for studies examining surface-bound antimicrobial activity. Biomaterial Functionalization One of the most important applications of LC-LL-37 is in biomaterial engineering. The N-terminal cysteine allows the peptide to be covalently attached to biomaterial surfaces, coatings, or scaffolds. By immobilizing antimicrobial peptides on medical device surfaces, researchers aim to create antimicrobial coatings that resist bacterial colonization and biofilm formation. Such strategies are of great interest for improving the safety of implants, wound dressings, and other biomedical materials. The conjugation capability of LC-LL-37 makes it particularly suitable for these surface functionalization studies. Investigating Membrane Disruption Mechanisms Because LL-37 interacts directly with lipid membranes, the modified peptide is frequently used in mechanistic studies of membrane disruption. Researchers use model membrane systems such as liposomes or supported lipid bilayers to analyze how the peptide binds, inserts, and perturbs membrane structure. These experiments help clarify how amphipathic peptides recognize microbial membranes and how membrane composition influences peptide activity. Role in Wound Healing and Tissue Repair LL-37 also contributes to wound healing processes, where it promotes epithelial cell migration, angiogenesis, and tissue regeneration. The peptide can influence signaling pathways involved in cell proliferation and extracellular matrix remodeling. Studies using LC-LL-37 allow researchers to explore how immobilized or modified peptides influence cell behavior and tissue repair mechanisms, particularly in biomaterials designed for regenerative medicine. Conclusion LC-LL-37 is a functionalized derivative of the human antimicrobial peptide LL-37 that incorporates an N-terminal cysteine for site-specific conjugation. This modification enables attachment of the peptide to surfaces or biomolecules while preserving its antimicrobial and immunomodulatory properties. Through applications in host defense studies, antimicrobial mechanism research, biomaterial functionalization, and investigations of immune signaling, LC-LL-37 provides a versatile tool for exploring the biological functions of cathelicidin peptides and for developing peptide-based strategies to combat infection and promote tissue repair.