Carbonylhydrazide-Based Molecular Tongs Inhibit Wild-Type and Mutated HIV-1 Protease Dimerization

Abstract

We have designed and synthesized new molecular tongs based on a rigid naphthalene scaffold and evaluated their antidimer activity on HIV-1 protease (PR). We inserted carbonylhydrazide and oligohydrazide (azatide) fragments into their peptidomimetic arms to reduce hydrophobicity and increase metabolic stability. These fragments are designed to disrupt the protein-protein interactions by reproducing the hydrogen bond pattern found in the antiparallel β-sheet formed between the N- and C-ends of the two monomers in the native PR. Kinetic analyses and fluorescent probe binding studies showed that several molecular tongs can inhibit PR dimerization. The best nonpeptidic molecular tongs to date were obtained with an inhibition constant K(id) of 50 nM for PR and 80 nM for the multimutated protease ANAM-11. The PR inhibition was selective, the aspartic proteases renin and pepsin were not inhibited.

Recent Progress in the Development of HIV-1 Protease Inhibitors for the Treatment of HIV/AIDS

“…Inhibitor 148 , with pseudopeptidic arms containing a hydrazine bridge, proved to be a very potent derivative with a K i of 50 nM. 191 …”

Development of peptide inhibitors of HIV transmission

“…As dimerization is necessary for proteolytic activity, prevention of dimerization effectively inhibits protease activity [178] , [193] . To improve upon the weak inhibitory potency of C-terminus and N-terminus mimics [194] , [195] , [196] , flexible linkers and rigid scaffolds have been used, as well as side chain tethering (intercalating “molecular tongs”) [113] , [197] , [198] , [199] , [200] and terminal modification with lipophilic groups and alkyl chains [201] , [202] , [203] , [204] . Interfacial peptides can also serve as irreversible inhibitors by covalently associating with protease [205] , [206] .…”

“…Another type of peptide inhibitor that targets dimerization is the fusion of N-terminal HIV-1 protease peptide with cell permeable domain of the HIV-1 Tat protein, which is the transactivator of the virus [190] , [207] . Peptide-based protease inhibitors require modulation to overcome the weak binding potency of inhibitors with the protein-protein interaction interface, which increases the complexity of drug design involving optimization of covalent modifications of peptide chains [198] . Prevalence of and similarities between families of proteases in the human body increases the standard for protease inhibitors in recognizing and inhibiting viral proteases and penetrating cell membrane [208] .…”

Dynamic covalent side‐chain cross‐links via intermolecular oxime or hydrazone formation from bifunctional peptides and simple organic linkers

“…Oxime‐functionalized amino acid residue X was synthesized in protected form as previously described . Hydrazide‐functionalized residue Z was incorporated into peptides using an Fmoc/2‐Cl‐Trt protected monomer, which was prepared from Cbz‐ l ‐Glu‐OBn ( 5 ) by adaptation of published methods (Scheme ) .…”