title: Covalent stabilization of coiled coils of the HIV gp41 N region yields extremely potent and broad inhibitors of viral infection.
abstract: Peptides from the N-heptad repeat region of the HIV gp41 protein can inhibit viral fusion, but their potency is limited by a low tendency to form a trimeric coiled-coil. Accordingly, stabilization of N peptides by fusion with the stable coiled-coil IZ yields nanomolar inhibitors [Eckert, D. M. & Kim, P. S. (2001) Proc. Natl. Acad. Sci. USA 98, 11187-11192]. Because the antiviral potency of IZN17 is limited by self-association equilibrium, we covalently stabilized the peptide by using interchain disulfide bonds. The resulting covalent trimer, (CCIZN17)3, has an extraordinary thermodynamic stability that translates into unprecedented antiviral potency: (CCIZN17)3 (i) inhibits fusion in a cell-cell fusion assay (IC50 = 260 pM); (ii) is the most potent fusion inhibitor described to date (IC50 = 40-380 pM) in a single-cycle infectivity assay against HIV(HXB2), HIV(NL4-3), and HIV(MN-1); (iii) efficiently neutralizes acute viral infection in peripheral blood mononuclear cells; and (iv) displays a broad antiviral profile, being able to neutralize 100% of a large panel of HIV isolates, including R5, X4, and R5/X4 strains. In all of these assays, the potency of N-peptide inhibitor (CCIZN17)3 was equal to or more than the C-peptide inhibitor in clinical use, DP178 (also known as Enfuvirtide and Fuzeon). More importantly, we show that the two inhibitors, which have different targets in gp41, synergize when used in combination. These features make (CCIZN17)3 an attractive lead to develop as an antiviral drug, alone or in combination with DP178, as well as a promising immunogen to elicit a fusion-blocking neutralizing antibody response.
authors.affiliation: Istituto di Ricerche di Biologia Moleculare P. Angeletti, 00040 Pomezia, Rome, Italy. elisabetta.bianchi@merck.com
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Bianchi
authors.forename: Marco
authors.initials: M
authors.lastname: Finotto
authors.forename: Paolo
authors.initials: P
authors.lastname: Ingallinella
authors.forename: Renee
authors.initials: R
authors.lastname: Hrin
authors.forename: Anthony V
authors.initials: AV
authors.lastname: Carella
authors.forename: Xiaoli S
authors.initials: XS
authors.lastname: Hou
authors.forename: William A
authors.initials: WA
authors.lastname: Schleif
authors.forename: Michael D
authors.initials: MD
authors.lastname: Miller
authors.forename: Romas
authors.initials: R
authors.lastname: Geleziunas
authors.forename: Antonello
authors.initials: A
authors.lastname: Pessi
mesh_terms: D019380:Anti-HIV Agents / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D002459:Cell Fusion; D002942:Circular Dichroism; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism; D004220:Disulfides / Q000737:chemistry / Q000378:metabolism; D000077560:Enfuvirtide; D015700:HIV Envelope Protein gp41 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D015658:HIV Infections / Q000188:drug therapy / Q000821:virology; D015497:HIV-1 / Q000187:drug effects* / Q000502:physiology*; D006801:Humans; D020128:Inhibitory Concentration 50; D008561:Membrane Fusion / Q000187:drug effects; D009500:Neutralization Tests; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D011489:Protein Denaturation; D020836:Protein Structure, Quaternary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013696:Temperature; D013816:Thermodynamics
chemical_list: C504981:(CCIZN17)3 protein; D019380:Anti-HIV Agents; D004220:Disulfides; D015700:HIV Envelope Protein gp41; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D000077560:Enfuvirtide; D003545:Cysteine