We have synthesized (CPC Scientific, Inc.) four stapled peptides, as depicted in Figure 2. We also synthesized the linear peptide, NYBSP-C, as a control. Besides, we purchased a linear peptide, SBP1, to use as a control, which was reported recently to bind to SARS-CoV-2 RBD with high affinity (KD = 47nM).
Abstract
Human angiotensin-converting enzyme 2 (ACE2) is the primary receptor of SARS-CoV-2 to enter the host cells and start the infection process. Therefore, it is prudent to design therapeutics based on the critical binding region of ACE2, which is a ∼30 aa long helix with a kink in the middle. However, the small peptide in solution may lose its helical conformation and subsequently lose its binding potential to the SARS-CoV-2 RBD, which it utilizes to bind to that helical region. Here we report the design of four stapled peptides based on that helix, which is expected to bind to SARS-CoV-2 with high affinity and prevent the binding of the virus to the ACE2 receptor and disrupt the infection. All stapled peptides showed high helical contents (50-94% helicity). On the contrary, the linear control peptide NYBSP-C showed no helicity (19%). We have evaluated the peptides in a pseudovirus based single-cycle assay in HT1080 and human lung cells, A549. Three of the four stapled peptides showed potent antiviral activity in HT1080 (IC50: 1.9 – 4.1 µM) and A549 cells (IC50: 2.2 – 2.8 µM). It is noteworthy that the stapled peptide, NYBSP-3, which showed the least helical content, also had the lowest antiviral activity in both cell lines. The linear peptides NYBSP-C and SBP1, reported recently to bind SARS-CoV-2 with KD of ∼47nM affinity, showed no antiviral activity. Most significantly, none of the stapled peptides show any appreciable cytotoxicity at the highest dose tested. We determined the proteolytic stability of one of the most active stapled peptides, NYBSP-4, in human plasma, which showed a half-life (T1/2) of >289 min.
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CPC Scientific Inc., a leading global peptide CRDMO (Contract Research, Development, and Manufacturing Organization) has invested in a new peptide API (Active Pharmaceutical Ingredient) manufacturing site, bringing many new jobs to Rocklin, California. The 41,000 sq ft facility located at 3880 Atherton Rd, Rocklin, CA 95765 will be utilized to manufacture clinical to commercial grade peptide products for increased manufacturing capacity and will diversify CPC Scientific’s supply chain.
CPC Scientific is entering an exciting period of growth and innovation for peptide and oligonucleotide therapeutic development and manufacturing, and we will continue to provide therapeutic APIs to pharmaceutical and biotech companies around the world. We are very pleased to partner with the City of Rocklin, California to bring manufacturing and Life-Science jobs to local American workers,” said Shawn Lee, PhD, CEO.
Ikeda, Z., Kakegawa, K., Kikuchi, F., Itono, S., Oki, H., Yashiro, H., Hiyoshi, H., Tsuchimori, K., Hamagami, K., Watanabe, M. and Sasaki, M. Journal of Medicinal Chemistry 65, no. 12 (2022): 8456-8477.
- Research, Takeda Pharmaceutical Company Limited, 26-1, Muraokahigashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
Subsequently, 5FAM–Abu–Gly–Asp–Asp–Asp–Lys–Ile–Val–Gly–Gly–Lys(CPQ2)–Lys–Lys–NH2 (purity: 97.2%, CPC Scientific, Inc.) was diluted with an assay buffer to prepare a 2.1 μM substrate solution.
The transferred energy from a fluorescent donor is converted into molecular vibrations if the acceptor is a non-fluorescent dye (quencher). When the FRET is terminated (by separating donor and acceptor), an increase of donor fluorescence can be detected. The design and synthesis work at CPC for FRET and TR-FRET peptide substrates include modification of sequences, selection of donor/quencher pairs, improvement of FRET substrate solubility and quenching efficiency.
Genomics research shows that more than a million proteins are encoded by approximately 30,000 human genes. Proteomics, the study of proteins encoded by the genome, includes identifying post-translational modifications, structural analyses, protein localization studies, and protein quantitation. Mass spectroscopybased techniques have evolved as a powerful tool in proteomics. Stable isotope-labeled peptides (SIL peptides) are chemically and physically indistinguishable from their endogenous counterparts concerning retention time, ionization efficiency, and fragmentation pathways.
Peptides play a vital role in the pharmaceutical industry and drug therapeutic development; however, their in vivo applications are sometimes limited due to fast degradation by proteases, poor solubility, antigenic responses, and glomerular filtration in the kidney. The covalent attachment of polyethylene glycol (PEG) chains to peptides is one approach that can reduce immunogenicity, improve solubility, and reduce renal clearance.
Hydrocarbon-stapled peptides are locked into their bioactive alpha-helical conformation through the site-specific introduction of a chemical brace, an all-hydrocarbon staple. The idea of peptide stapling was introduced to overcome the limitations of two broad classes of therapeutic agents (small molecules and protein biologics) in targeting intracellular protein-protein interactions. Small molecules only work on proteins with a specific surface feature, and most protein biologics do not penetrate cells. Because stapled peptides are locked into a stabilized α-helical structure (the most common element of protein secondary structures), they can easily penetrate cells.
![Locmi-AKH-I, cycloAKH (cyclo[LNFTPNWG]](https://test.cpcscientific.com/wp-content/uploads/2022/05/cyclo-LNFTPNWG-v2-1500sm.png)
Mogford, Jon E., George E. Davis, Steven H. Platts, and Gerald A. Meininger. Circulation research 79, no. 4 (1996): 821-826.
Locmi-AKH-I, cycloAKH (cyclo[LNFTPNWG]
CPC Scientific is pleased to announce and welcome David A. Godkin as VP of Business Operations! David will be responsible for the growth and development of our HR department and facilities management division. He brings 20+ years of experience in human resources and facility operations from the peptide industry. We are confident David will have […]
Bekdemir, Ahmet, Eden EL Tanner, Jesse Kirkpatrick, Ava P. Soleimany, Samir Mitragotri, and Sangeeta N. Bhatia Advanced Healthcare Materials (2022): 2102685.
Peptides [TDN-qFAM, C-(PEG)2-K(CPQ2)-GGGSRPfGG-5FAM] were obtained from Tufts University Peptide Core Facility or CPC Scientific, Inc (USA)
