Design of antiviral stapled peptides containing a biphenyl cross-linker

Abstract

Here we report the design and synthesis of a panel of stapled peptides containing a distance-matching biphenyl cross-linker based upon a peptide capsid assembly inhibitor reported previously. Compared with the linear peptide, the biphenyl-stapled peptides exhibited significantly enhanced cell penetration and potent antiviral activity in the cell-based infection assays. Isothermal titration calorimetry and surface plasmon resonance experiments revealed that the most active stapled CAI peptide binds to the C-terminal domain of HIV capsid protein as well as envelop glycoprotein gp120 with low micromolar binding affinities, and as a result, inhibits both the HIV-1 virus entry and the virus assembly.

Conformational Restriction of Peptides Using Dithiol Bis-Alkylation

“…Then, they scanned the peptide for the best ( i , i +4) staple location by moving the cysteines and then cross-linking with linker mxy ( Jo et al, 2012). Similarly, Muppidi et al designed stapled helices containing cysteines in ( i , i +7) positions, using the longer linkers 4,4′-bis-bromomethyl-biphenyl and 6,6′-bis-bromomethyl-[3,3′]bipyridine (Muppidi et al, 2011, 2014) (see Fig. 1).…”

“…Fig. 1 lists commercially available or readily synthesized linkers that have been used to cross-link cysteine-containing peptides, which range from simple ortho , meta , and para dibromomethylxylenes ( oxy , mxy , and pxy , respectively) to 2,3-bis (bromomethyl)quinoxaline ( Jo et al, 2012; Muppidi et al, 2011, 2014; Timmerman et al, 2005). While nearly all prior reports have used L-cysteine, one reported application used D-cysteine as the thiol-containing amino acid (Muppidi et al, 2011).…”

Stapling peptides using cysteine crosslinking

“…While all crosslinked peptides exhibited higher binding affinity to Mcl‐1 than the parent linear peptide, cell uptake was more profound with constrained peptides featuring highly lipophilic crosslinkers. Other examples of biphenyl crosslinking with concomitant cell penetration enhancement include the stapling of a monomeric GCN4 peptide allowing DNA binding, a phage‐display derived peptide inhibitor of the p53‐mdmd2/‐mdmx interaction and a capsid assembly inhibitor with blocking activity against HIV‐1 virus entry …”

Synthesis of cell-permeable stapled BH3 peptide-based Mcl-1 inhibitors containing simple aryl and vinylaryl cross-linkers

“…13–15 For example, we reported a simple side chain cross-linking chemistry based on the distance-matching biaryl cross-linkers, 12 and successfully employed this strategy in designing the cell-permeable and proteolytically stable stapled Noxa BH3 peptides as potent Mcl-1 inhibitors, 16 the stapled peptide-based dual inhibitors of Mdm2/Mdmx, 17 and a dual-active stapled peptide that binds to the C-terminal domain of HIV capsid protein as well as the envelop glycoprotein gp120 and inhibits HIV-1 virus entry and assembly. 18 …”