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.
Abstract
Background
Previously, we reported the conversion of the 12-mer linear and cell-impermeable peptide CAI to a cell-penetrating peptide NYAD-1 by using an i,i + 4 hydrocarbon stapling technique and confirmed its binding to the C-terminal domain (CTD) of the HIV-1 capsid (CA) protein with an improved affinity (Kd ~ 1 μM) compared to CAI (Kd ~ 15 μM). NYAD-1 disrupts the formation of both immature- and mature-like virus particles in in vitro and cell-based assembly assays. In addition, it displays potent anti-HIV-1 activity in cell culture against a range of laboratory-adapted and primary HIV-1 isolates.
Results
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. Unlike NYAD-1, the i,i + 7 peptides did not have any effect on virus release; however, they impaired Gag precursor processing. HIV-1 particles produced in the presence of these peptides displayed impaired infectivity. Consistent with an effect on virus entry, selection for viral resistance led to the emergence of two mutations in the gp120 subunit of the viral envelope (Env) glycoprotein, V120Q and A327P, located in the conserved region 1 (C1) and the base of the V3 loop, respectively.
Conclusion
The i,i + 7 stapled peptides derived from CAI unexpectedly target both CA and the V3 loop of gp120. This dual-targeted activity is dependent on their ability to penetrate cells as well as their net charge. This mechanistic revelation will be useful in further modifying these peptides as potent anti-HIV-1 agents.
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Boehm, M., Beaumont, K., Jones, R.M., Kalgutkar, A.S., Zhang, L., Atkinson, K., Bai, G., Brown, J.A., Eng, H., Goetz, G.H. and Holder, B.R. Journal of Medicinal Chemistry (2017).
- Pfizer Worldwide Research & Development, Cambridge, Massachusetts 02139, United States
- Pfizer Worldwide Research & Development, Groton, Connecticut 06340, United States
The chemokine receptor CXCR7 is an attractive target for a variety of diseases. While several small-molecule modulators of CXCR7 have been reported, peptidic macrocycles may provide advantages in terms of potency, selectivity, and reduced off-target activity
Bainbridge, Travis W., et al. Scientific Reports 7.1 (2017): 12524.
- Protein Chemistry, Molecular Oncology, Discovery Chemistry, Cancer Immunology, and Neuroscience. Genentech Inc., South San Francisco, CA, 94080, USA
"ANP FAP and aP NIRF were synthesized by CPC Scientific (Sunnyvale, CA)… Another internally-quenched FRET peptide substrate (ANPFAP) for FAP has recently been reported and demonstrated for use as an activity-based, in vivo imaging tool. The peptide sequence contains two internal Gly-Pro dipeptide motifs, susceptible to FAP cleavage and a Cy5.5/QSY21, quenched-FRET pair."
Coorens, Maarten, et al. The Journal of Immunology 199.4 (2017): 1418-1428.
"CATH-2 and LL-37 were synthesized by Fmoc-chemistry at CPC Scientific (Sunnyvale, CA)."
Tcholakov, I., Grimshaw, C.E., Shi, L., Kiryanov, A., Murphy, S.T., Larson, C.J., Plonowski, A. and Ermolieff, J. Bioscience Reports 37, no. 3 (2017): BSR20170275.
- Departments of In Vitro Pharmacology, Immunology, Enzymology and Biophysical Chemistry, Medicinal Chemistry, External Innovation, Metabolic Disease, In Vitro Pharmacology, and Gastrointestinal and Enterology Discovery Unit, Takeda California, Inc., 10410 Science Center Drive, San Diego, CA 92121, U.S.A
The substrate used for our PHD2 kinetic study was a 17-mer peptide mimicking the sequence of HIF-1a surrounding the Pro564 residue hydroxylated by the PHD enzymes (Biotin-DLEMLAPYIPMDDDFQL). The substrate used for FIH1 was a 34-mer peptide mimicking the sequence of HIF-1α surrounding residue Asn803 (DESGLPQLTSYDCEVNAPIQGSRNLLQGEELLRAL). Both peptides were synthesized by CPC Scientific Inc.
Wilson, Sarah S., et al. PLoS Pathogens 13.6 (2017): e1006446.
"Cryptdin 2 (UniProtKB: P28309, LRDLVCYCRTRGCKRRERMNGTCRKGHLMYTLCCR)... obtained by oxidative refolding of partially purified linear peptides (synthesized by CPC Scientific...) and purifying the correctly folded species by reverse-phase high-pressure liquid chromatography (RP-HPLC). Purity was determined by analytical RP-HPLC, and the mass of the disulfide-bonded peptides was verified by high mass accuracy liquid chromatography-mass spectrometry."
Sattiraju, A., et al. Oncotarget 2017, 8 (26), 42997-43007.
For Ac-225 labeling, the prepared DOTA-Pep-1L (CPC-scientific, San Jose, CA) was incubated with Ac-225 at 70°C for 50 minutes. The TLC plates were scanned on a BioScan Imaging Scanner. Cu-64 was purchased from Washington University in St. Louis. The custom peptide specific to IL13RA2 and a scrambled peptide were conjugated with NOTA by CPC scientific Inc (San Jose, CA). Both the peptides, Pep-1L and scrambled peptide-NOTA were radiolabeled with Cu-64 according to the previously reported methods [15].
Puthenveetil, Sujiet, et al. PloS One 12.5 (2017): e0178452.
- Worldwide Medicinal Chemistry, Pfizer Global R&D, Groton, Connecticut, United States of America.
- Pfizer Oncology Research, Pearl River, NY, United States of America.
"Peptide-payload conjugate (7) was prepared by reacting 2mM aizoacetyl-Ser-Lys-Gly-Ser-Lys (CPC scientific, inc. Sunnywale, CA) with 8 mM NHS-ester payload [19] in 50% Dimethyl sulfoxide (DMSO), 50 mM borate buffer pH 8.5 for 2 h at 37°C."
Kwon, Ester J., et al. Advanced Materials 29.35 (2017).
"[..] synthesized for initial screening with FAM-conjugated lysine at the C-terminal end of the membrane-interactive peptide and with or without D[KLAKLAK]2 on the C-terminus using standard Fmoc chemistry[..] All peptides were synthesized with N-terminal myristic acid and C-terminal amine. [..] larger quantities of the peptides were synthesized by CPC Scientific to 90% purity"
Noland, Cameron L., et al. Proceedings of the National Academy of Sciences 114.30 (2017): E6044-E6053.
- Departments of Structural Biology, Infectious Diseases, Biochemical and Cellular Pharmacology, Pathology, Translational Immunology, and Biomolecular Resource Group, Genentech, Inc., South San Francisco, CA 94080.
"..peptide substrates were synthesized based on the Pal lipoprotein, Pal peptideshort (Pam2Cys-SSNKNGGK-Biotin; CPC Scientific, Inc.).."