It was found that RLF-100 (Aviptadil) is associated with rapid respiratory failure recovery among COVID-19 Patients. The clinical findings may be based on evidence that VIP inhibits the replication of the SARS-CoV-2 virus in human lung cells and immune cells (monocytes). No other antiviral agent has demonstrated rapid recovery from viral infection and demonstrated laboratory inhibition of viral replication. It is a patented formulation of aviptadil (synthetic human Vasoactive Intestinal Polypeptide, VIP), which has been granted FDA fast track designation, FDA emergency use IND authorization, and an expanded access protocol. Aviptadil is an injectable formulation of the vasoactive intestinal polypeptide (VIP) in combination with the adrenergic drug phentolamine.
Coronavirus receptor binding domain. The key receptor binding domain (residues 319-541) is highlighted in yellow. Variable amino acid residues between SARS-CoV-2 and SARS-CoV are highlighted in cyan. Tyr 489, Asn 487, Gln 493, Tyr 505 are important for ACE2 binding.
LifeTein can help in your research with custom peptide synthesis of the following specific proteins: SARS-CoV-2 Receptor Binding Domains, SARS-CoV-2 Nucleocapsid Fragments, T-cell and B-cell Epitopes of SARS-CoV-2, Fusion Inhibitors Targeting HR1 Domain of the SARS-CoV-2 Spike Proteins, Inhibitors of SARS-CoV-2 Mpro/3CLpro/C30 Endopeptidase, ACE2 Inhibitors and Substrates, and AT2 Receptor Agonists and Antagonists.
Pool of 22 peptides derived from a peptide design (15mers with 5 aa overlap) through the receptor binding domain of S1 protein.
Direct antimicrobial mechanisms of cationic host defense peptides
The cationic host defense peptides (CHDP), also known as antimicrobial peptides, could be used to kill enveloped viruses such as the 2019 Novel Coronavirus SARS-CoV-2. The peptides have the potential to destabilize the viral envelope on contact, damaging the virions and inhibiting infectivity. The specific antiviral peptide may bind to cellular receptors involved in viral infection or peptide-mediated aggregation of viral particles. The antiviral peptides could create an ‘antiviral shield’ at mucosal surfaces and prevent replication and spread of the Coronavirus if upregulated after the initial infection.
During pandemics, where there is insufficient time to produce vaccines (such as the outbreak of respiratory illness Covid-19 first detected in Wuhan, China), the cationic host defense peptides could be the first-line antiviral treatments.
Some of the antimicrobial peptides are the human cathelicidin LL-37 and β-defensins. Cathelicidins are immunomodulatory antimicrobials with an important role in the regulation of the inflammatory response. The only human cathelicidin, LL-37, is the most well-studied peptide in this family. LL-37 is an α-helical peptide. While defensins have a common β-sheet core stabilized with three disulfide bridges between six conserved cysteine residues.
Direct antimicrobial mechanisms of cationic host defense peptides can be mediated by membrane translocation of the peptides followed by binding to intracellular targets such as nucleic acids and/or proteins to kill bacteria. Proline-rich antimicrobial peptides use inner membrane transporters as Trojan horses to gain entry and bind to intracellular targets such as nucleic acids or nascent proteins. And subsequently affect cell processes such as replication, transcription, translation, protein folding, and cell wall synthesis.
At this stage, only a few peptide-derived treatments have made it to market such as PAC-113, a histatin analog, and dalbavancin, a semisynthetic lipoglycopeptide.
Despite the limited understanding of structure-function relationships, the potential of peptide-based therapies remains a promising new clinical direction for the Coronavirus.
The extensive structural analyses have revealed that interactions between SARS-CoV spike protein receptor-binding domain (RBD) and its host receptor angiotensin-converting enzyme 2 (ACE2), which regulate both the cross-species and human-to-human transmissions of SARS-CoV.
Studies showed that the sequence of 2019-nCoV coronavirus RBD, including its receptor -binding motif (RBM) that directly contacts ACE2 and uses ACE2 as its receptor with much higher affinity (10-20 times higher!) than SARS.
Several critical residues in 2019-nCoV RBM may provide favorable interactions with human ACE2 such as Gln493 and Asn501.
A total of nine cysteine residues are found in the RBD, six of which forming three pairs of disulfide bonds. Among these three pairs, two are in the core (Cys336-Cys361 and Cys379-Cys432) to help stabilize the β sheet structure while the remaining one (Cys480-Cys488) connects loops in the distal end of the RBM.
2019 Novel Coronavirus SARS-CoV-2 is a virus identified as the cause of an outbreak of respiratory illness Covid-19 first detected in Wuhan, China.
To help expedite Covid-19 research, LifeTein synthesized a 69 amino acid spike glycoprotein with one disulfide bond in 6 days. This effort is a partnership with a biotech company for drug development.
Cyclic peptides as broad-spectrum antiviral agents
Antiviral drugs and vaccines are the most powerful tools to combat viral diseases. Most drugs and vaccines only target a single virus. However, the broad-spectrum antivirals can be used for rapid management of new or drug-resistant viral strains. Cyclized peptides and peptide analogs are excellent examples of broad-spectrum antivirals.
An artificial peptide molecule was found to neutralize a broad range of group 1 influenza A viruses, including H5N1. The peptide design was based on complementarity determining region (CDR) loops have been reported for other viral targets. The optimized peptides bind to the highly conserved stem epitope and block the low pH-induced conformational rearrangements associated with membrane fusion.
These peptidic compounds and their advantageous biological properties should accelerate development of novel small molecule and peptide-based therapeutics against influenza virus.
The linear peptide is Suc-SQLRSLEYFEWLSQ-NH2. Three cyclization strategies were used: head to tail, side chain to side chain and side chain to tail. An ornithine (Orn) side chain was fused with the carboxyl terminus of β-alanine for lactam formation.
Check here for more details: Potent peptidic fusion inhibitors of influenza virus, Science 28 Sep 2017, DOI: 10.1126/science.aan0516
Lately, more broad-spectrum antiviral agents were found to target viruses. It was found that 55 compounds can target eight different RNA and DNA viruses. Dalbavancin is a novel lipo-glycopeptide antibiotic. The lipoglycopeptide disrupts bacterial cell wall formation by binding to
the terminal d-alanyl-d-alanine peptidoglycan sequence in Gram-positive bacteria in a linear, concentration-dependent manner. The dalbavancin has effects on echovirus 1, ezetimibe against HIV1 and Zika virus.
More details: https://www.ncbi.nlm.nih.gov/pubmed/29698664
Protein Purification Using Magnetic Beads: Top Tips for Success
Magnetic bead-based protein purification offers a powerful solution for various applications like high-throughput microscale purification, pull-down/CoIP experiments, and protein-protein or protein-DNA interaction studies. Here’s why magnetic beads are the top choice: they can be coated with specific affinity ligands for antigens, antibodies, proteins, or nucleic acids. Moreover, magnetic beads are non-porous and have a defined diameter, eliminating hidden surfaces where molecules can stick, leading to reduced background, simplified purification, and streamlined washing steps. Compared to traditional bead separation methods involving agarose, sepharose, or silica beads, magnetic bead separation stands out as the quickest, cleanest, and most efficient technique.
If you’re new to working with magnetic beads, here are some essential tips to ensure success:
Thorough Resuspension: Ensure uniformity across aliquots by thoroughly resuspending your magnetic beads. These nano-superparamagnetic beads are covalently coated with highly functional groups, providing increased binding capacity and better dispersion. Since magnetic beads are composed of iron oxide and can settle over time, it’s crucial to vortex and resuspend them thoroughly before use to redisperse the beads.
Enhanced Washing: Minimize non-specific binding by increasing the number of washing steps. Whether you’re using ethanol or the recommended wash buffer, make sure to use an adequate volume of wash solution to cover the bead pellet.
Understanding Functional Groups: Different beads are covalently coated with various functional groups like maleimide, primary amine, NHS, carboxylic acid, purified streptavidin, protein A, reduced glutathione, nickel-charged nitrilotriacetic acid, or groups for DNA/RNA purification. These coatings, along with buffer conditions, affect bead properties. Understanding these specifics is essential for proper bead handling.
Efficient Bead Capture: Magnetic beads typically form a pellet attracted to the magnet within a minute. Extend the attraction time to ensure efficient bead capture.
Gentle Supernatant Removal: When removing the wash solution or supernatant, angle the pipette tip to avoid disturbing the magnetic bead pellet. Ensure that the tip doesn’t come into contact with the pellet.
By following these tips, you can make the most of magnetic bead-based protein purification, improving the efficiency and reliability of your experiments.
Giantin, a novel conserved Golgi membrane protein, is a disulfide-linked homodimer. It was found that BFA-induced Golgi disorganization is associated with the monomerization of giantin.
The pull-down experiment was performed. The control peptide biotin-GHGTGSTGSGSMLRTLLRRRL synthesized by LifeTein was incubated with lysate and Dynabeads, as well as the lysate incubated with Dynabeads only served as a control. Dynabeads carrying MGAT1 peptide were able to pull-down giantin from the lysate of HeLa cells, however, giantin was not detected in the pull-down fraction from the lysate exposed to the Dynabeads or in combination with control peptide. It is logical to hypothesize that the MGAT1 binding domain of giantin lies within its N-terminal non-coiled-coil area.
The Dynabeads function similarly to LifeTein magnetic beads: https://www.lifetein.com/peptide-product/amineactivated-peptide-conjugation-magnetic-beads-p-3647.html
LifeTein provides the fastest turnaround time and most reliable quality in the industry. Peptides are made in New Jersey, USA. Projects move from conception to bench in only 3–5 days so you can deal with your research deadlines.
Introducing LifeTein‘s faster microwave peptide synthesis technology! LifeTein’s new platform is designed for maximized speed and efficiency. Unparalleled peptide quality, greater flexibility, and improved reliability make LifeTein the vendor of choice for all your peptide synthesis needs.
Difficult peptides such as beta-Amyloid in hours rather than days
4-minute cycle time
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