DISCOVERY Peptides

  • Anti-Microbial Peptides: Focus on LL-37

    Cathelicidins form a distinct class of proteins that are key components of the innate and adaptive immune response. They also play a role in apoptosis, inflammation, phagocytosis and angiogenesis. The hallmark of the cathelicidin family of proteins is the presence of a highly conserved cathelin domain. Cathelicidins are expressed as inactive precursor proteins and their proteolytic cleavage leads to the release of active mature peptides ranging from 12 to 88 amino acids. The dominant mature cathelicidin antimicrobial peptide (CAMP) is LL-37 in humans, and cathelicidin-related antimicrobial peptide (CRAMP) in rodents.

    The LL-37 peptide is a 37-residue with two leucine residues at the N-terminus. LL-37 contains an N-terminal helical structure and a flexible C-terminal region. LL-37 belongs to the class of α-helical antimicrobial peptide (AMPs) and possesses amphipathic properties. The bioactive peptides exhibit a broad-spectrum of antimicrobial activity against bacteria, viruses, and fungi. LL-37 can interact with invading pathogens, permeabilise the membranes and subsequently neutralise the activities of endotoxins, such as lipopolysaccharide.

    Cathelicidin peptides can act directly and indirectly to regulate the activity of various cells in the immune system. LL-37 is a multifunctional signalling peptide that possesses various immunomodulatory activities. Depending on the environment and the stage of disease pathogenesis, LL-37 can exhibit both pro-and anti-inflammatory activity. A multitude of receptors recognize LL-37, where it can stabilize and trigger their activity and regulate downstream immunoregulatory mediators.  LL-37 can also induce cytokines and chemokines release and acts as a potent chemoattractant and an adjuvant.

    Available to order from our Discovery® catalogue:

    LL-37 acid (catalogue number: crb1000007)

    LL-37 amide (catalogue number: crb1000864)

    Labelled LL-37 peptides available soon

    Biotin-LL-37 (catalogue number: crb1000836)

    [5-FAM]-LL-37 (catalogue number: crb1000837)

    Fragments

    LL13-37 (catalogue number: crb1000034)

    LL17-29 (catalogue number: crb1000035)

    LL17-32 (catalogue number: crb1000036)

    Mouse

    CRAMP (1-39) (catalogue number: crb1000262)

  • 10% Discount On Your First DISCOVERY® Purchase

    We are offering a 10% discount off your first purchase from DISCOVERY® Peptides & Antibodiesusing the code : ENDEAVOUR10

    The code is valid across all products on the DISCOVERY® Peptides site and also on our sister site DISCOVERY® Antibodies.

  • Peptide Substrates: Focus on LRRKtide

    Mutations in the Leucine-rich repeat kinase-2 (LRRK2) gene have been associated with familial and sporadic Parkinson’s disease (PD), which is the second most common neurodegenerative disorder worldwide after Alzheimer’s. LRRK2 is a multi-domain protein that contains an LRR (leucine rich repeats) motif, a COR (C-terminal of Ras of Complex) domain, a WD40 (Trp-Asp 40) motif and two distinct functional domains; a GTPase domain and a protein kinase domain. The majority of pathological mutations in LRRK2 are clustered within the three domains that form the enzymatic core. The most prevalent mutant form of LRRK2 is the Gly2019Ser mutation, which up-regulates LRRK2 kinase activity. Gly2019 is located within the Asp-Tyr-Gly-Mg2+-binding motif of the kinase domain.

    Moesin was identified as a physiological substrate of LRRK2 in a kinase substrate tracking and elucidation (KESTREL) screen using rat brain extracts. Belonging to the ezrin/redixin/moesin ERM family of proteins, Moesin functions as an anchor between actin-based cytoskeletons and plasma membranes. Analysis of radiolabelled phosphopeptides, derived from LRRK2 phosphorylated Moesin, mapped Thr558 as a phosphorylation site. LRRK2 was also shown to phosphorylate ezrin (Thr567) and radixin (Thr564) at residues equivalent to Moesin Thr558; consequently, the LRRKtide peptide (RLGRDKYKTLRQIRQ) from Moesin that encompasses the Thr558 was derived.  Although LRRKtide contains both threonine and tyrosine residues, LRRK2 acts on LRRKtide predominately as a serine/threonine kinase and not as a tyrosine kinase.

    LRRKtide is widely used for the enzymatic characterization of LRRK2 kinase activity and inhibition studies and is considered to be a more efficient substrate for quantitative assays, compared to measuring LRRK2 auto-phosphorylation. Multiple studies have used LRRKtide to assess the effects of pathogenic mutations on LRRK2 kinase activity and as LRRK2 is clinically linked to PD, LRRK2 kinase has been considered as a therapeutic target. In addition, LRRKtide has been used for comparing the efficiencies of Mg2+ and Mn2+ divalent metal ions as ATP cofactors, to support LRRK2 kinase activity.

    Novel LRRK2 kinase inhibitors have been identified and evaluated from a library of compounds using high-throughput screening that detects LRRKtide phosphorylation using mass spectrometry. The diverse use of LRRKtide has contributed to a better understanding of the role of LRRK2 in Parkinson’s Disease, and provides further possibilities for future investigations into combating the neurodegenerative disorder.

     

    LRRKtide

    http://www.discoverypeptides.com/lrrktide

    crb1000328

     

    LRRKtide amide

    http://www.discoverypeptides.com/lrrktide-amide

    crb1000258

     

    Phosphorylated LRRKtide

    http://www.discoverypeptides.com/phosphorylated-lrrktide

    crb1000466

  • Focus on Myelin Oligodendrocyte Glycoprotein (MOG)

    Myelin oligodendrocyte glycoprotein (MOG) is a type I integral membrane protein on the extracellular surface of oligodendrocytes in the outermost lamellae of the myelin sheath. MOG can exist as monomeric and dimeric species. Its extracellular localisation facilitates its functions as a homophilic adhesion receptor, where it plays a role in the completion, compaction and maintenance of the myelin.

    Multiple sclerosis (MS) is an inflammatory, demyelinating and neurodegenerative disorder of the central nervous system (CNS) characterized by myelin destruction and axonal degeneration. MOG has been identified as a key autoantigen for demyelination in MS and experimental autoimmune encephalomyelitis (EAE), an animal model that resembles MS. Although MOG is a minor component of the CNS, it is highly immunogenic and can stimulate the activation of T-cell and B-cell responses.

    Immunization of rodents with native or recombinant MOG or synthetic MOG derived peptides induces an inflammatory response and initiates an immune response against myelin, causing damage and degeneration of the CNS. A number of MOG peptide fragments have shown to be encephalitogenic determinants, including MOG (1-22), MOG (35-55), MOG (92-106). Crystal structure studies of the MOG extracellular domain in a homodimer complex reveal that residues within the MOG 1-22, 35-55 and 92-106 map onto the face of the β-sheet and participate in the dimerization interface. This suggests a link between the dimeric form of MOG and a failure of immunological tolerance to MOG seen in MS.

    Studies using various MOG derived peptides show that the MOG (35-55) fragment is the most potent encephalitogen and the immunodominant epitope for T cell response.  MOG (35-55) induced EAE models can be used to recapitulate all three MS subtypes, which are relapsing-remitting MS (RRMS), primary progressive MS (PPMS) and secondary progressive MS (SPMS). Depending on the MOG (35-55) dose, immunized mice are presented with varying degrees of neuropathogical impairment, immune infiltration, ascending paralysis, demyelinating lesions, axon loss and gliosis in the spinal cord and brain. MOG (35-55) induced EAE models can provide an insight into elucidating the immunopathological mechanism of MS progression and facilitate in the development of novel therapeutics.

     

    MOG (35-55) acid Mouse, Rat

    crb1000205

    http://www.discoverypeptides.com/mog-35-55-mouse-rat

     

    MOG (35-55) amide Mouse, Rat

    crb1000379

    http://www.discoverypeptides.com/mog-35-55-amide-mouse-rat

     

    MOG (92-106) Mouse, Rat

    crb1000330

    http://www.discoverypeptides.com/mog-92-106-mouse-rat

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