Gyrase B Inhibitor Impairs HIV-1 Replication by Targeting Hsp90 and the Capsid Protein

• DOI: 10.1074/jbc.m110.155275
• Publication Date: 2010-10-12T05:25:21Z
• Authors: Luciano Vozzolo; Belinda Loh; Paul J. Gane; Maryame Tribak; Lihong Zhou; Ian Anderson; Elisabeth Nyakatura; Richard G. Jenner; David Selwood; Ariberto Fassati
• Keywords: Aminocoumarins; 0301 basic medicine; Protein Conformation; Microbiology; Protein Structure, Tertiary; 3. Good health; 03 medical and health sciences; DNA Gyrase; HIV-1; Mutagenesis, Site-Directed; Humans; Topoisomerase II Inhibitors; Capsid Proteins; HSP90 Heat-Shock Proteins; Cyclophilin A; Dimerization; HeLa Cells; Protein Binding

Chemical genetics is an emerging approach to investigate the biology of host-pathogen interactions. We screened several inhibitors of ATP-dependent DNA motors and detected the gyrase B inhibitor coumermycin A1 (C-A1) as a potent antiretroviral. C-A1 inhibited HIV-1 integration and gene expression from acutely infected cell, but the two activities mapped to distinct targets. Target discovery identified Hsp90 as the C-A1 target affecting viral gene expression. Chromatin immunoprecipitation revealed that Hsp90 associates with the viral promoter and may directly regulate gene expression. Molecular docking suggested that C-A1 binds to two novel pockets at the C terminal domain of Hsp90. C-A1 inhibited Hsp90 dimer formation, suggesting that it impairs viral gene expression by preventing Hsp90 dimerization at the C terminus. The inhibition of HIV-1 integration imposed by C-A1 was independent of Hsp90 and mapped to the capsid protein, and a point mutation at residue 105 made the virus resistant to this block. HIV-1 susceptibility to the integration block mediated by C-A1 was influenced by cyclophilin A. Our chemical genetic approach revealed an unexpected function of capsid in HIV-1 integration and provided evidence for a role of Hsp90 in regulating gene expression in mammalian cells. Both activities were amenable to inhibition by small molecules and represent novel antiretroviral drug targets.