HIV-1 group O integrase displays lower enzymatic efficiency and higher susceptibility to raltegravir than HIV-1 group M subtype B integrase

• Published in: Antimicrobial agents and chemotherapy 2014-12, Vol.58 (12), p.7141-7150
• Main Authors: Depatureaux, Agnès, Quashie, Peter K, Mesplède, Thibault, Han, Yingshan, Koubi, Hannah, Plantier, Jean-Christophe, Oliveira, Maureen, Moisi, Daniela, Brenner, Bluma, Wainberg, Mark A
• Format: Article
• Language: English
• Subjects: 3' Flanking Region; Antiviral Agents; Binding Sites; Binding, Competitive; Cloning, Molecular; Drug Resistance, Viral; Escherichia coli - genetics; Escherichia coli - metabolism; Gene Expression; HIV Integrase; HIV Integrase - chemistry; HIV Integrase - classification; HIV Integrase - genetics; HIV Integrase Inhibitors; HIV Integrase Inhibitors - chemistry; HIV-1; HIV-1 - chemistry; HIV-1 - enzymology; Human immunodeficiency virus 1; Humans; Kinetics; Molecular Docking Simulation; Protein Binding; Pyrrolidinones; Pyrrolidinones - chemistry; Raltegravir Potassium; Recombinant Proteins - chemistry; Recombinant Proteins - genetics
• ISSN: 0066-4804; 1098-6596
• DOI: 10.1128/AAC.03819-14

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.