• CPC Scientific Inc., 160E Tasman Dr., Suite 200, San Jose, CA 95134

[..] assembling the peptide on the Rink Amide resin and attaching the PEG azide moiety to the N-terminal Lys, the Dde group was removed as previously shown and coupled to the Fmoc-PEG2-acid. Removal of the Fmoc followed by simultaneously click/coupling to bicyclo[6.1.0]non-4-yn-9-ylmethyl (2,5-dioxopyrrolidin-1-yl) carbonate gave 1c which was deprotected and cleaved from the resin to give 1c.

• Chinese Peptide Company, Hangzhou Economic and Technical Development Zone, China, 310018.

"The D-VEGF-A polypeptide chain (COOH acid, residues 8-109 (1)) was chemically synthesized using solid phase peptide synthesis (SPPS) and native chemical ligation, and folded to form the protein covalent homodimer, using methods adapted from our previous work [..]"

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).

1. Pfizer Neusentis, The Portway Building, Granta Park, Cambridge, UK.
2. Pfizer Worldwide Research & Development, Eastern Point Road, Groton, Connecticut 06340, USA.
3. CPC Scientific Inc., 1245 Reamwood Avenue, Sunnyvale, CA 94089, USA.

"antipeptide (EGVYVHPV), angiotensin II, human (DRVYIHPF), and isotopically (13C) labeled heptapeptide (AAAAHAA-NH2 [where “A” indicates a carbon thirteen (13C) "Synthesis was conducted at CPC Scientific Inc. Ac-Asp(OtBu)-Thr(tBu)-His(Trt)-Phe-Pro-Ile-Cys(Trt)-Ile-PhePEG3-Arg(Pbf)-Arg(Pbf)-Lys(Boc)-wang resin (2).. Ac-Asp-Thr-His-Phe-Pro-Ile-Cys-Ile-Phe-PEG3-Arg-Arg-Lys(BODIPY_TMR_C6)."

To date only two entry inhibitors are available, Maraviroc which targets the co-receptor CCR5 3;4 and Enfuvirtide, a peptide drug which interacts with the N-terminal heptad repeat of gp41 of HIV to form an inactive hetero six-helix bundle preventing infection of host cells 5;6. Despite the success achieved with the HAART the emergence of resistant viruses and the side effects of these therapies highlight the need of novel anti-retroviral agents to overcome these problems.

In this report, we expanded the study to i,i+7 hydrocarbon-stapled peptides to delineate their mechanism of action and antiviral activity. We identified three potent inhibitors, NYAD-36, -66 and -67, which showed strong binding to CA in NMR and isothermal titration calorimetry (ITC) studies and disrupted the formation of mature-like particles. They showed typical α-helical structures and penetrated cells; however, the cell penetration was not as efficient as observed with the i,i+4 peptides.

1. Pfizer Worldwide Research & Development, Pfizer, Inc., Groton, Connecticut 06340, United States
2. CPC Scientific, Hangzhou, P.R. China

All peptides used in this study (Table 1) were synthesized by an Fmoc/t-Butyl solid-phase strategy on a 2-chlorotrityl chloride resin preloaded with the Fmoc-Thr(tBu)-OH. Amino acid derivatives were obtained from CPC Scientific (Sunnyvale, CA)

"Synthetic peptides that specifically bind nuclear hormone receptors offer an alternative approach to small molecules for the modulation of receptor signaling and subsequent gene expression. [..] Using a number of biophysical techniques, including crystal structure analysis of receptor–stapled peptide complexes, we describe in detail the molecular interactions and demonstrate that all-hydrocarbon staples modulate molecular recognition events."