Peptides

<p>GALA is a synthetic pH sensitive peptide designed to better understand viral fusion proteins interaction with membranes. This could ultimately lead to better drug delivery systems by more efficient cell entry and escape from the endosome to enter the nucleus.GALA is 30 amino acids long, sufficient to span the lipid bilayer. The EALA repeats are designed to create a hydrophobic face that can allow lipid interaction when GALA is in an alpha helical conformation. Glutamic acid is inserted with the EALA repeats to create a pH-dependent negatively charged sidechain.  In neutral pH conditions GALA is in a random coil conformation. In acidic conditions (pH 5) GALA forms an amphipathic helix which can bind to the lipid bilayer. The interaction varies depending on the composition of the lipid membrane. Most importantly, interaction with negative or neutrally-charge bilayers leads to the formation of a transbilayer pore formed of approximately 10 GALA peptides. GALA has already been utilised for this purpose at low pH to deliver genes into the nucleus of cells in vitro. The composition of the membrane effects the formation and bilayer-destabilizing properties of GALA however, GALA has a strong potential for future applications for the delivery of genes, DNA and drugs into the cell.</p>

<p>Forms of inherited muscular dystrophy such as Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) result from mutations targeting the dystrophin gene. These disorders are X-linked, progressive, and cause the gradual weakening of the muscles leading to respiratory failure and ultimately reduces the patient lifespan.In DMD, mutations lead to the production of premature stop codons and hence the truncated dystrophin protein product is vulnerable to nonsense mediated decay and degradation. Therefore, dystrophin production in muscle cells is reduced. On the other hand, nonsense mutations which also contribute to DMD, cause exon skipping in BMD and result in an internally truncated protein product which are partially functional. The symptoms of BMD are later onset compared with DMD which develop in patients between 2 to 7 years.Treatments of dystrophin disorders are in clinical trial including antisense oligonucleotide exon skipping and gene therapy. However, the efficacies of these treatments are not easily quantified. Currently levels of muscular dystrophin are quantified by western blot which can be unreliable. The peptide provided here, aligning residues dystrophin (2690-2700), has been tested via mass spectrometry to provide a more reliable method of validation of dystrophin levels. Further study with this dystrophin fragment could prove to be a vital step in the understanding and treatment of dystrophin disorders. Within our catalogue we also have other peptides tested for dystrophin quantification available plus the full-length dystrophin protein.</p>

<p>Glucagon (1-29)-[Cys(Cy5)] is derived from glucagon, which is a peptide hormone secreted by alpha cells located in the islet of Langerhans region of the pancreas. Glucagon is an essential catabolic hormone that is responsible for the regulation of blood glucose levels. Once released into the bloodstream, glucagon stimulates the production of hepatic glucose, which means it is considered to be a glucose-mobilizing agent. Excessive levels of glucagon can result in the development of hyperglycaemia, since the action of glucagon results in abnormally high blood glucose levels.This peptide contains Cyanine 5 (Cy5), which is a widely used red fluorescent dye.</p>

<p>Infliximab is a biologic medicine used in the treatment of numerous autoimmune diseases including Crohn disease, rheumatoid arthritis, and ankylosing spondylitis. Infliximab binds with high affinity to tumour necrosis factor-α (TNF-α) blocking most of the cytokine effects, which includes mediating the inflammatory responses. Infliximab is a chimeric human-mouse IgG monoclonal antibody- the constant regions of the heavy and light chains are human-derived. The heavy chain peptide (46-60) has been identified as an antigen for antigen-specific T cell analysis. Numerous methods of immunological analysis can be applied to this peptide to hopefully provide further insight to these autoimmune conditions.</p>

<p>Histone H3 (1-20)-[S]-Biotin is derived from Histone 3 (H3) which is one of the four core histones (H2A, H2B, H3 and H4) fundamental in compacting eukaryotic DNA into a structure known as the nucleosome. The nucleosome arises when 147 base pairs of DNA wrap around a H3-H4 tetramer and two H2A-H2B dimers, forming the histone octamer core. Both H4 and H3 are highly conserved and perform roles in binding to segments of DNA which enter and leave the nucleosome and in chromatin formation. Similar to the other core histone, H3 has a globular domain and a flexible N-terminal domain, 'histone tail' which can undergo modifications such as acetylation, methylation, phosphorylation and ubiquitination. Due to histones containing a large number of lysine and arginine residues they have a positive net charge which interacts in an electrostatic manner with the negatively charged phosphate groups in DNA. The transcriptional activation or silencing of the chromatin is controlled by ATP-dependent chromatin remodelling factors and histone modifying enzymes which target histone proteins. Both processes function to alter the positioning of the nucleosome, allowing the DNA it to be either available or inaccessible to the transcription machinery.Another modification process histones can undergo is biotinylation where the covalent attachment of a biotin molecule is catalysed by the enzyme Biotinidase. This cleaves biocytin to generate a biotinyl-thiester intermediate. The biotinyl can then be transferred onto the histone lysine ɛ-amino group which in this case it is covalently attached to Histone 3. Overall the biotinylation sites identified in histone 3 are: K4, K9 and K18. The presence of biotinylated histones have been detected in human cells such as lymphocytes and lymphomas.</p>

<p>Trans-activator of transcription (TAT) is a key protein from simian immunodeficiency virus (SIV). SIVs are retroviruses which cause often non-pathogenic infections of members of the simian species (monkey). Human immunodeficiency virus strains (HIV) developed from the SIV's. During HIV infection a small amount of TAT protein is produced early on which binds to an RNA stem-loop structure, the trans-activating response element (TAR), located at the 5' ends of HIV-1 transcripts, this binding results in increased production of full-length viral RNA. This positive feedback loop allows HIV to have an explosive response once a threshold level of TAT is produced, helping it defeat the bodies immune response. TAT protein also associates with RNA polymerase II complexes during early transcription elongation. TAT is also released into the host bloodstream where it can be absorbed by neighbouring, uninfected cells. TAT is toxic to these cells and induces apoptosis and inhibition of T-cell proliferation, thus assisting in the progression toward AIDS. Thus, TAT appears to be involved in both host immune suppression and viral dissemination.TAT is being investigated as a therapeutic target and as an agent to be used in a potential HIV vaccine.</p>

<p>Flagellin is the structural protein which forms the major portion of bacterial flagella filaments. The N- and C- terminals of flagellin are highly conserved regions, whereas the central core can vary greatly between bacterial species. Flagellin 22 (flg22) is the most conserved stretch of amino acids across bacterial species and is located towards the N-terminal of flagellin.Flg22 is a potent elicitor of plant immune responses and is recognised in plants by the membrane bound leucine-rich repeat-receptor kinase FLAGELLIN SENSITIVE 2 (FLS2). Flg22 induces defence gene expression to trigger both local and systemic immune responses and is thus widely used in plant defence studies.Truncated flagellin 22 (flg22-θ”2) represents amino acids 1-20 of flg22. It is a strong and selective agonist of tomato FLS2, with weak agonist activity towards Arabidopsis FLS2 even at high concentrations.</p>

<p>Scrambled peptide of JAG-1(188-204). Jagged - 1 is a cell surface ligand for in the Notch pathway. Notch receptors and ligands are present on the extracellular service of cells and require cell-cell contact for engagement. Ligand binding to Notch receptors results in the proteolytic cleavage of membrane-bound Notch receptors, thus allowing the intercellular region to be transported to the nucleus and become a transcriptional activator. The ligand-induced Notch activation is regulated by E3 ubiquitin ligases, Mindbomb1 (Mib-1) and Neuralized.JAG1 is widely expressed throughout mammalian development, across many tissues and developmental stages. Notch signalling plays a critical role in cellular fate determination including muscle cell differentiation, neurogenesis, and the development of the sensory regions of the inner ear- heart- kidney- eye- lung and other tissues.Jag-1 has been implicated in breast- cervical- colorectal- endometrial- gastric- head and neck- ovarian- hepatocellular- lung- pancreatic- prostate, and kidney and adrenocortical cancers, leukemia and lymphoma. Co-overexpression of Notch-1 and Jagged-1 predicts the poorest overall cancer survival. JAG1 mutations have also been associated Alagille syndrome.</p>

<p>Influenza A nucleoprotein (NP) residues 147-155 (TYQRTRALV) is from a conserved region of the nucleoprotein that is positively selected. NP (147-155) is an effective immunodominant CTL epitope MHC allele H-2Kd in mice that can induce an effective antigen-specific immunity. This was validated by HLA binding and cytotoxicity assays in human cells.  Immunisation of mice with the NP (147-155) offers protection against a fatal dosage of influenza. In addition, the NP (147-155) epitope can stimulate antigen-specific T cells in T cell assays such as ELISPOT to understand humoral responses to viral infection. Further work with the NP (147-155) epitope can help new flu vaccine design to provide more effective protection. This epitope is provided with a C-terminal biotin sequence for easier purification and detection.</p>

<p>Natalizumab LC46-58 KGN deimmunised</p>

Native Melan-A (26-35) decapeptide derives from the melanocyte lineage-specific protein Melan-A/MART-1, which is expressed in almost 75-100% of primary and metastatic melanomas. The region 26-35 of Melan-A protein acts as an antigenic peptide that is recognized by CD8+ tumor-reactive cytolytic T lymphocytes (CTLs) for designing antigen-specific cancer vaccines1. It has been shown that CD8+ Melan-A-specific CTLs isolated from melanoma patients efficiently lyse the Melan-A-expressing HLA-A*0201+ melanoma cell line. However, CTLs preferentially recognize the Melan-A (26-35) peptide as compared with the Melan-A (27-35) peptide. Moreover, the Melan-A (26-35) A27L analog (ELAGIGILTV) has a higher binding affinity to HLA-A*0201 than the native Melan-A (26-35) peptide (EAAGIGILTV), and consequently displays more potent antigenicity and immunogenicity. It has been reported that the concentration of Melan-A (26-35) A27L analog required to obtain 50% of maximal antigenic activity (EC50) is 0.01nM, whereas that of the native Melan-A (26-35) peptide is 0.25nM1. Therefore, the relative activity of Melan-A (26-35) A27L analog is 25 fold higher than that of the native Melan-A (26-35) peptide. Furthermore, functional competition assay has shown that the concentration of Melan-A (26-35) A27L analog required to achieve 50% inhibition (IC50) of tumor lysis is 2nM, which is 10 fold lower than that of the native Melan-A (26-35) peptide. Regarding peptide stability in human serum, the half-lifes (t1/2) of the native Melan-A (26-35) peptide and the A27L analog are quite similar (45 and 40min, respectively) as measured by HPLC-ESI-MS, but much higher than that of the Melan-A (27-35) nonapeptide (5min).

Histone H3 (1 - 21) K4Me3 is derived from Histone 3 (H3) which is one of the four core histones (H2A, H2B, H3 and H4) fundamental in compacting eukaryotic DNA into the nucleosome. The nucleosome arises when 147 base pairs of DNA wrap around a H3-H4 tetramer and two H2A-H2B dimers, forming the histone octamer core. Both H4 and H3 are highly conserved and perform roles in binding to segments of DNA which enter and leave the nucleosome and in chromatin formation. Similar to the other core histone, H3 has a globular domain and a flexible N-terminal domain, 'histone tail' which can undergo modifications such as acetylation, methylation, phosphorylation and ubiquitination. Due to histones containing a large number of lysine and arginine residues they have a positive net charge which interacts in an electrostatic manner with the negatively charged phosphate groups in DNA. The transcriptional activation or silencing of the chromatin is controlled by ATP-dependent chromatin remodelling factors and histone modifying enzymes which target histone proteins. Both processes function to alter the positioning of the nucleosome, allowing the DNA it to be either available or inaccessible to the transcription machinery.Lysine 4 of Histone H3 (1 - 21) K4Me3 has been tri-methylated.

<p>SARS-CoV-2 ORF3a (26-40)</p>

<p>ANP (1-28) is derived from the atrial natriuretic peptide (ANP) which is a cardiac hormone involved in maintaining cardio-renal homeostasis. This occurs through the activation of the guanylyl cyclase-coupled receptor, resulting in the increased concentration of cyclic guanylate monophosphate. Moreover its function in the processes of anti-proliferation and anti-angiogenesis allow it to take part in cardiovascular remodelling.ANP is a member of the natriuretic peptide family and it is encoded by the NPPA gene, located on chromosome 1. Once synthesized from the 151 amino acid pre-prohormone into its biologically active form, ANP is secreted by the atrial cardiomyocytes in the circulating forms: ANP (1-98) and ANP (99-126). This synthesis process involves the signal peptide being removed from the pre-prohormone resulting in pro-ANP (1-126) which is converted into the circulating forms by the type II transmembrane serine protease Corin.</p>

Fluorescein labelled amyloid β 1-15 (Aβ1-15 ). Aβ1-15 is one of many short Aβ species found in vivo and is formed by the cleavage of Aβ precursor protein by β- and alpha-secretase.Amyloid β-protein (Aβ) has been identified as the key subunit of the extracellular plaques found in the brains of patients with Alzheimer's disease (AD) and Down's syndrome (DS). Aβ has therefore been extensively studied as a potential target for treatment of AD.Aβ is formed from the cleavage of the large, transmembrane protein- APP (amyloid precursor protein). Cleavage of APP by β- and then γ-secretases results in the formation of Aβ. Aβ can aggregate to produce amyloid-β oligomers, which are thought to be highly neurotoxic. Over time Aβ can further aggregate to produce the characteristic senile plaques present in AD and DS. Aβ can be degraded by enzymes such as neprilysin, insulin degrading enzyme or endothelin converting enzyme. At physiological levels Aβ may be involved in controlling synaptic activity and neuronal survival.Fluorescein (FAM) is a hugely popular fluorescent tag due to its excellent fluorescence quantum yield and relatively high absorptivity as well as being highly water soluble.

<p>The histone H2A residues 1-20 are derived from histone 2A (H2A) which is one of the four core his-tones (H2A, H2B, H3 and H4) fundamental in compacting eukaryotic DNA into a structure known as the nucleosome. The nucleosome arises when 147 base pairs of DNA wrap around a H3-H4 tetramer and two H2A-H2B dimers, forming the histone octamer core.At the site of DNA entry on the outer nucleosome, the C-terminus of H2A is present and is able to interact with linker histones or other factors. This allows for variation and changes in nucleosome stability to occur. Furthermore Histone H2A has histone variants such as H2A.Z and H2A.X (which are present in all organisms) and these variants alter the organisation of the DNA.Due to histones containing a large number of lysine and arginine residues they have a positive net charge which interacts in an electrostatic manner with the negatively charged phosphate groups in DNA. The transcriptional activation or silencing of the chromatin is controlled by ATP-dependent chromatin remodelling factors and histone modifying enzymes which target histone proteins. Both processes function to alter to change the positioning of the nucleosome, allowing the DNA it to be either available to the transcription machinery or inaccessible.</p>

<p>Neurotensin (NT) is involved in food absorption in the gut as well as acting as a neurotransmitter in the central nervous system (CNS). In the intestine, NT increases fatty acid translocation, in part by increasing intestinal blood flow. In the CNS, NT regulates pathways associated with ghrelin and leptin which mediate satiety and food ingestion. NT is also involved in the regulation of Luteinizing hormone (LH) and Prolactin release and also plays a role in hypotension- analgesia- gut contraction- vascular permeability- maintaining energy homeostasis- fat storage and metabolic disorders. Higher plasma pro-NT levels are associated with obesity and insulin resistance. NT is therefore a potential target for treating obesity-related diseases.NT is secreted from neuroendocrine cells in the small intestine upon fat intake and exerts its physiological actions by binding three NT receptor (NTR) types- NTR1, NTR2, and NTR3.NTR1 is highly expressed in various tumour cells including- small cell carcinoma/small cell lung cancer (SCLC)- meningiomas- astrocytomas- glioblastoma- pancreatic and colonic carcinoma, and breast and prostate cancers. NTR1 is therefore a possible target for novel cancer therapy.</p>

<p>HLA-A*02 is a class I major histocompatibility complex (MHC) allele which is part of the HLA-A group of human major histocompatibility complex (MHC) leukocyte antigens (HLA). HLA-A is a human MHC class I cell surface receptor and is involved in presenting short polypeptides to the immune system. These polypeptides are typically 7-11 amino acids in length and originate from proteins being expressed by the cell. Cytotoxic T cells in the blood "read" the peptide presented by the complex and should only bind to non-self peptides. If binding occurs, a series of events is initiated culminating in cell death via apoptosis. New York oesophageal squamous cell carcinoma 1 (NY-ESO-1) is part of a well-characterized group of cancer/testis antigens (CTAs). Normally, NY-ESO-1 expression is restricted to germ cells and placental cells, however NY-ESO-1 is also expressed in several cancers including: neuroblastoma- myeloma- metastatic melanoma- synovial sarcoma as well as bladder- oesophageal- hepatocellular- head and neck- non-small cell lung- ovarian- prostate and breast cancers and is often associated with poor prognosis. NY-ESO-1 is also able to elicit a spontaneous immune response, being the most immunogenic among the CTA family members and is therefore the most promising CTA candidate target for cancer immunotherapy.NY-ESO-1 is coexpressed with melanoma antigen gene C1, a member of the MAGE family of CTAs which is involved in cell cycle progression and apoptosis.</p>

Apelin (65-76), human is derived from the apelin peptide which acts as a ligand for the apelin receptor (APJ) G protein coupled receptor and is a substrate for angiotensin converting enzyme 2. Preprapelin, encoded for by APLN located on Xq25-26.1, is cleaved to form either apelin 36 or apelin 17, 12 and 13. As a member of the adipokine hormone family, which are involved in processes such as vascular homeostasis and angiogenesis, the apelin is secreted from adipose tissue.Apelin has been found to be expressed in the spinal cord and the human brain and when performing immunohistochemistry it was observed that apelin-17 is significantly expressed in the human heart, brain, lungs and endothelial cells.Both apelin and the apelin receptor are widely distributed around the body thus apelin has been found to be associated with cardiovascular diseases, obesity, diabetes and cancer. Studies exploring myocardial infarction showed there to be greater apelin mRNA expression during human heart failure compared to in healthy tissue. Apelin protects against heart failure due to, the pyroglutamyl form of apelin, playing a role in decreasing infarct size of myocardial infarctions. Furthermore in rats with hypertension, the expression of apelin and APJ was decreased.

<p>This C-terminal Sortagging peptide acts as a (oligo)glycine nucleophile in the final steps of a sortagging protein labelling reaction. This reaction results in the fluorescent moiety being attached to the C-terminus of the target protein or peptide.A substrate peptide containing the LPXTG motif is recognised and cleaved by the enzyme Sortase A (SrtA) from Staphylococcus aureus. The catalytic cysteine residue in the active site of SrtA, serves as a nucleophile to cleave the peptide bond between threonine and glycine of the substrate peptide. Cleavage results in the formation of a thioacyl intermediate between the substrate peptide and SrtA. This intermediate is then resolved by the N-terminus of this (oligo)glycine nucleophile peptide, resulting in the creation of a new peptide bond that links the substrate peptide to this peptide and its fluorescent dye.  This method of protein labelling is known as sortagging.This peptide contains Sulfocyanine5, which is a fluorescent red dye.</p>