Histone H3K27M is a driving mutation in diffuse intrinsic pontine glioma (DIPG), a deadly pediatric brain tumor. The malignant and treatment-resistant brain tumor is a target for anti-cancer studies.

Through a global inhibition of PRC2 catalytic activity and displacement of H3K27me2/3, H3K27M reshapes the epigenome and promotes oncogenesis of DIPG. Consequentially, the histone modification H3K36me2, antagonistic to H3K27me2/3, is elevated. The relationship and role of H3K36me2 in H3K27M-DIPG was investigated by approaches to its upstream catalyzing enzymes, NSD1 and NSD2, the “writers”, and its downstream binding factors, LEDGF and HDGF2, the “readers”.

Tumor-promoting transcriptional programs in H3K27M-DIPG were found to be disrupted by loss of NSD1 and NSD2, thus impeding cellular proliferation and tumorigenesis.
Downstream, a chemically modified peptide mimicking endogenous H3K36me2 was found to dislodge LEDGF and HDGF2 from chromatin. As LEDGF and HDGF2 are the main readers mediating the protumorigenic effects downstream of NSD1/2-H3K36me2, dislodging them resulted in inhibition of H3K27M-DIPG proliferation.

In this study, the chemically modified peptides used were cell penetrating peptides purchased from LifeTein.

Reference: Sci. Adv. 2021 Jul 14; 7(29)

BRAF is the most frequently mutated kinase in human cancers and is one of the major effectors of oncogenic RAS. So BRAF is a target of interest for anti-cancer drug development.

Two FDA-approved inhibitors, dabrafenib and vemurafenib have been developed as inhibitors for BRAF. These ATP-competitive inhibitors potently inhibit the most common BRAF variant V600E. However, current BRAF inhibitors could induce drug resistance and paradoxical activation. New approaches and drug candidates are needed to disrupt the intact dimer interface of BRAF. The 10-mer peptide inhibitor braftide was designed using a computational approach to block RAF dimerization. It was found that the peptide inhibitor triggers selective protein degradation of BRAF and MEK through proteasome-mediated protein degradation in cells.

The combination of ATP competitive inhibitors and braftide eliminates paradoxical activation. This alternative strategy will improve the efficacy of current ATP-competitive inhibitors. The RAF dimer interface could be a promising therapeutic target.

Braftide is a 10-mer peptide TRHVNILLFM. Braftide disrupts BRAF dimers and inhibits BRAF kinase activity. Braftide causes degradation of BRAF leading to destabilized MAPK complexes. Braftide synergizes with ATP-competitive inhibitors like Dabrafenib to mitigate paradoxical MAPK activation and downregulate MAPK signaling.

In this study, the Braftide, Null-Braftide, TAT-PEGlinker-Braftide, and TAT peptides were purchased from LifeTein with TFA removal.

Reference: ACS Chem Biol. 2019 Jul 19; 14(7): 1471–1480.

LifeTein recently announced a significant accomplishment in peptide synthesis: the successful creation of the C subunit of the ATP synthase. This subunit is a highly hydrophobic peptide composed of 75 residues and plays a crucial role in cellular energy processes. Its structure is characterized by a transmembrane α-helical “hairpin” formation, typically assembled into oligomers of 8-16 units, varying with species, within the mitochondrial inner membrane.

The intriguing aspect of the C subunit is its spontaneous folding into a β-sheet conformation. The peptide’s far-UV circular dichroism (CD) spectrum analysis verified this unique structural formation. Intriguingly, the β-sheet conformation of the c subunit can lead to the formation of aggregates. The process of cross-β aggregate formation was carefully observed using the amyloid-binding dye Tiofavin T (TT). A pivotal discovery in this study was the identification of the essential role of Ca2+ in guiding the folding and self-assembly of the c subunits. This process influences the formation of oligomers, as opposed to fibrils.

Amyloidogenic peptides are known for their ability to form ion channels in lipid bilayers, and the human synthetic c subunit synthesized by LifeTein is no exception. This amyloidogenic peptide forms oligomers capable of creating ion-conducting pores in planar lipid bilayers. Interestingly, these oligomers present similarities in ion channel formation with other amyloids and synuclein, albeit with lower conductances compared to the canonical PTP. These misfolded forms of the c subunit, potentially toxic, could play a significant role in cellular pathophysiology, offering insights into various diseases.

This synthesis and study of the ATP synthase’s C subunit mark a notable advancement in peptide research, contributing valuable knowledge to the field of biochemistry and molecular biology.

For more detailed information, the original study can be accessed here: Nature Article on ATP Synthase C Subunit.

LifeTein’s work not only showcases the complexity of peptide synthesis but also opens avenues for further exploration in understanding protein structures and their implications in health and disease.

Reference: https://www.nature.com/articles/s41598-021-88157-z.pdf

Human cytomegalovirus (HCMV) is currently a major cause of congenital disease in newborns and organ failure in transplant recipients. Various vaccine strategies have been developed, including live attenuated, recombinant viral proteins, dense bodies, vector vaccine subunit, or synthetic peptide epitopes. The rabbit polyclonal anti-gM and anti-gN antibodies were elicited by vaccinating animals with synthesized peptide sequences of gM (1-13aa and 345-372aa) and gN (61-101aa). Animal immunization and sera collection were performed at Lifetein, LLC (Hillsborough, NJ, USA). The sera were affinity-purified by its corresponding peptides.

These formulations have been extensively tested using different animal models and have shown promising immunogenicity and protective efficacy. Some of these strategies have already progressed to clinical trials with humans. The study was studied by Vaccine Analytical Research Development and Vaccine Process Development Merck & Co., Inc., Kenilworth, NJ, USA.

LifeTein FRET peptide helped researchers identify a small molecule drug candidate, DMA-135, against Enterovirus 71 (EV71), a virus that causes foot-to-mouth disease with no FDA approved drugs.

The Tat-derived FRET peptide, (5-FAM)-AAARKKRRQRRRAAA-Lys(TAMRA), from LifeTein, binds strongly to the SLII (Stem Loop II) of Enterovirus 71 (EV71) with a dissociation constant Kd of 24.5 +/-4.7 nM. It has been recently used in the fluorescent indicator displacement assay (FID assay) and helped to identify a potential drug candidate, DMS-135, from the small molecule library, capable of internal ribosome entry site (IRES) targeting to block viral replication.

For the FID assay, when the peptide is bound to RNA, FRET is facilitated, allowing for excitation of FAM (485nm) and emission detection from TAMRA (590nm). When the small molecule drug candidate displaces the peptide from the RNA (SLII) secondary structure, the FRET is disabled, and TAMRA is not fluorescent. Such displacement and fluorescence change allow quantification of the binding affinity of the small molecules on the target RNA.

The peptide and its FID assay may prove generally useful in screening and identifying small molecules for viral RNA binding and inhibition.

The SARS-CoV-2 virus (a.k.a. 2019-nCoV; disease: COVID-19) is responsible for the plague year of 2020. The Pfizer-BioNTech and Moderna mRNA vaccines have now been approved for emergency use and more are coming down the pipeline.

The best vaccine should be high safety, low cost, and ease of production and administration. This paper described an interesting citizen-science vaccine based on synthetic peptides.

Synthetic peptide synthesis provides the freedom to design epitopes of sufficient length for immunogenic stimulation but is predicted not to trigger these serious side effects. Synthetic peptides are inexpensive and can be made to order quickly. Many simple linear epitopes can be generated without special conformational constraints. The peptide antigens can be delivered by nanoparticles intranasally.

The following peptide sequences were chosen as self-administered vaccines at about 5 to 7 micrograms of each peptide per dose of vaccine.

1. Spike 436-460, a.k.a. Spike1, NSNNLDSKVGGNYNYLYRLFRKSN
2. Spike 462-476, KPFERDISTEIYQAd
3. Spike 478-502, kPCNGVEGFNCYFPLQSYGhQPTNG
4. Spike 550-574cir, cgLTESNKKFLPFQQgGRDIADTcD
5. Spike 375cir, cSrdYNSASFSTFKsYGVSPTKcND
6. Spike 522cir, CGPKKSTNLVKNKsVNFNFNcd
7. Spike 804-820cir, cILPDPSKPSKRSFcgD
8. Spike 802-823cir, FSQcLPDPSKPSKRSFcEDLLF
9. Orf1ab 1544-1564cir (non-circularized), cFHLDGEVITFDNLKTLLSLREct
10. Spike 462-501, KPeERDgSTEIYQAGSTPCNGVEGFNCYFPLQSYGFQPTN

Order your testing sample peptides from here: https://www.lifetein.com/peptide-product/peptide-vaccine-testing-samples-p-11049.html

Transmembrane serine protease 2 (TMPRSS2) is a serine protease that in humans is encoded by the TMPRSS2 gene. It is a cell surface protein primarily expressed by endothelial cells across the respiratory and digestive tracts. The protein contains a type II transmembrane domain, a receptor class A domain, a scavenger receptor cysteine-rich domain and a protease domain.

Recent evidence suggested that SARS-CoV-2 uses the ACE2 receptor for cell entry, in synergy with the host’s TMPRSS2. The viral S glycoprotein is cleaved by TMPRSS2, thus facilitating viral activation. As TMPRSS2 is a serine protease, it primes the spike-domain (S) of SARS-CoV-2 by cleaving as the S1/S2 sites. TMPRSS2 activity is crucial for cell entry and viral pathogenesis. In a recent in vitro study by Hoffmann et al., the TMPRSS2 inhibitor camostat mesylate blocked the SARS-CoV-2 entry into primary lung cells, suggesting that TMPRSS2 could represent a potential target in SARS-CoV-2 treatment. This drug is approved for clinical use already in Japan for unrelated illnesses and could serve to be an important therapy for COVID-19.

A highly conserved cryptic epitope in the receptor-binding domains of SARS-CoV-2, LT5578, was cited by Nature (Potently neutralizing and protective human antibodies against SARS-CoV-2, volume 584, pages443–449(2020)). This peptide was synthesized in 6 days. This is part of the receptor-binding domain (RBD). It is a critical determinant of virus-receptor interaction and thus of viral host range and tropism. The RBD also includes important viral-neutralizing epitopes (21–23), and it may be sufficient to raise a protective antibody response in inoculated animals.

Two potently neutralizing monoclonal antibodies, COV2-2196 and COV2-2130, which recognize non-overlapping sites, bound simultaneously to the S protein and neutralized wild-type SARS-CoV-2 virus in a synergistic manner.

Lately, a recombinant SARS-CoV-2 Spike S (S1+S2) Protein was produced by LifeTein. The amino acid sequences of recombinant protein was derived from (Q14 – Q1208) of accession# YP009724390.1. The SARS-CoV-2 spike (S) protein is composed of two subunits; the S1 subunit contains a receptor-binding domain that engages with the host cell receptor angiotensin-converting enzyme 2 and the S2 subunit mediates fusion between the viral and host cell membranes. The S RBD protein plays key parts in the induction of neutralizing-antibody and T-cell responses, as well as protective immunity, during infection with SARS-CoV-2 (2019-nCoV) as in recent COVID-19 outbreak.

LifeTein successfully synthesized Aureocin A53, a highly cationic 51-residue peptide containing ten lysine and five tryptophan residues,   Formyl-MSWLNFLKYIAKYGKKAVSAAWKYKGKVLEWLNVGPTLEWVWQKLKKIAGL, using solid-phase peptide synthesis approach. A53 is a Class II bacteriocins. It was originally isolated from Staphylococcus aureus A53 and is active against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus. The mode of action was proposed as insertion into lipid bilayer and consequent membrane leakage. The solid-phase peptide synthesis provide an inexpensive alternative to isolation from bacteria culture or recombinant expression.

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.