title: HIV-1 group O integrase displays lower enzymatic efficiency and higher susceptibility to raltegravir than HIV-1 group M subtype B integrase.
abstract: HIV-1 group O (HIV-O) is a rare HIV-1 variant characterized by a high number of polymorphisms, especially in the integrase coding region. As HIV-O integrase enzymes have not previously been studied, our aim was to assess the impact of HIV-O integrase polymorphisms on enzyme function and susceptibility to integrase inhibitors. Accordingly, we cloned and purified integrase proteins from each of HIV-1 group O clades A and B, an HIV-O divergent strain, and HIV-1 group M (HIV-M, subtype B), used as a reference. To assess enzymatic function of HIV-O integrase, we carried out strand transfer and 3' processing assays with various concentrations of substrate (DNA target and long terminal repeats [LTR], respectively) and characterized these enzymes for susceptibility to integrase strand transfer inhibitors (INSTIs) in cell-free assays and in tissue culture, in the absence or presence of various concentrations of several INSTIs. The inhibition constant (Ki) and 50% effective concentration (EC50) values were calculated for HIV-O integrases and HIV-O viruses, respectively, and compared with those of HIV-M. The results showed that HIV-O integrase displayed lower activity in strand transfer assays than did HIV-M enzyme, whereas 3' processing activities were similar to those of HIV-M. HIV-O integrases were more susceptible to raltegravir (RAL) in competitive inhibition assays and in tissue culture than were HIV-M enzymes and viruses, respectively. Molecular modeling suggests that two key polymorphic residues that are close to the integrase catalytic site, 74I and 153A, may play a role in these differences.
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada.
authors.forename: Agnès
authors.initials: A
authors.lastname: Depatureaux
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Quashie
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada.
authors.forename: Thibault
authors.initials: T
authors.lastname: Mesplède
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada.
authors.forename: Yingshan
authors.initials: Y
authors.lastname: Han
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada.
authors.forename: Hannah
authors.initials: H
authors.lastname: Koubi
authors.affiliation: Laboratoire associé au Centre National de Référence du VIH, Hopital Charles Nicole, CHU de Rouen, Rouen, France.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Plantier
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada.
authors.forename: Maureen
authors.initials: M
authors.lastname: Oliveira
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada.
authors.forename: Daniela
authors.initials: D
authors.lastname: Moisi
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada.
authors.forename: Bluma
authors.initials: B
authors.lastname: Brenner
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada mark.wainberg@mcgill.ca.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Wainberg
mesh_terms: D024509:3' Flanking Region; D001665:Binding Sites; D001667:Binding, Competitive; D003001:Cloning, Molecular; D024882:Drug Resistance, Viral; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D019427:HIV Integrase / Q000737:chemistry* / Q000145:classification / Q000235:genetics; D019428:HIV Integrase Inhibitors / Q000737:chemistry*; D015497:HIV-1 / Q000737:chemistry* / Q000201:enzymology; D006801:Humans; D007700:Kinetics; D062105:Molecular Docking Simulation; D011485:Protein Binding; D011760:Pyrrolidinones / Q000737:chemistry*; D000068898:Raltegravir Potassium; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D019428:HIV Integrase Inhibitors; D011760:Pyrrolidinones; D011994:Recombinant Proteins; D000068898:Raltegravir Potassium; D019427:HIV Integrase; C514801:p31 integrase protein, Human immunodeficiency virus 1