title: Peptide inhibitors of HIV-1 integrase dissociate the enzyme oligomers.
abstract: Integration of HIV-1 genome into host cell chromosome is mediated by viral integrase (IN). The IN catalytic core (CC, IN(50-212)) dimerizes through mutual interactions of its alpha1 and alpha5 helices. Peptides INH1 and INH5 reproducing these helix sequences strongly inhibited IN. For instance, an IC(50) of 80 nM was determined for INH5 in integration assays using wild-type IN (wtIN). In size exclusion chromatography, INH1 and INH5 perturbed the association-dissociation equilibrium of both dmIN (IN(1-288)/F185K/C280S) and CC, leading to monomers as surviving species, while in circular dichroism, binding of peptides to dmIN altered the protein conformation. Thus, enzyme deactivation, subunit dissociation, and protein unfolding are events which parallel one another. The target of INH5 in the enzyme was then identified. In fluorescence spectroscopy, C(0.5) values of 168 and 44 nM were determined for the binding affinity of INH5 to IN and CC, respectively, at 115 nM subunit concentration, while interaction of INH5 with INH1 was found stronger than interaction of INH5 with itself (23 times larger in term of dissociation constants). These results strongly suggested that the alpha1 helix is the privileged target of INH5. The latter could serve as a lead for the development of new chemotherapeutic agents against HIV-1.
authors.affiliation: Département de Biologie et Pharmacologie Structurales, Laboratoire de Physicochimie et de Pharmacologie des Macromolécules Biologiques, UMR 8532 CNRS, Institut Gustave Roussy, 94805 Villejuif, France.
authors.forename: R G
authors.initials: RG
authors.lastname: Maroun
authors.forename: S
authors.initials: S
authors.lastname: Gayet
authors.forename: M S
authors.initials: MS
authors.lastname: Benleulmi
authors.forename: H
authors.initials: H
authors.lastname: Porumb
authors.forename: L
authors.initials: L
authors.lastname: Zargarian
authors.forename: H
authors.initials: H
authors.lastname: Merad
authors.forename: H
authors.initials: H
authors.lastname: Leh
authors.forename: J F
authors.initials: JF
authors.lastname: Mouscadet
authors.forename: F
authors.initials: F
authors.lastname: Troalen
authors.forename: S
authors.initials: S
authors.lastname: Fermandjian
mesh_terms: D000595:Amino Acid Sequence; D019380:Anti-HIV Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D002942:Circular Dichroism; D019281:Dimerization; D019427:HIV Integrase / Q000737:chemistry* / Q000378:metabolism*; D019428:HIV Integrase Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D011487:Protein Conformation / Q000187:drug effects; D017433:Protein Structure, Secondary / Q000187:drug effects; D017434:Protein Structure, Tertiary / Q000187:drug effects; D016662:Virus Integration / Q000187:drug effects
chemical_list: D019380:Anti-HIV Agents; D019428:HIV Integrase Inhibitors; D010446:Peptide Fragments; D019427:HIV Integrase