Abstract
Binding to the primary receptor, CD4, triggers conformational changes in the metastable HIV-1 envelope glycoprotein (Env) trimer ((gp120-gp41)3) that are important for virus entry into host cells. These changes include an 'opening' of the trimer, creation of a binding site for the CCR5 co-receptor and formation and/or exposure of a gp41 coiled coil. Here we identify a new compound, 18A (1), that specifically inhibits the entry of a wide range of HIV-1 isolates. 18A does not interfere with CD4 or CCR5 binding, but it inhibits the CD4-induced disruption of quaternary structures at the trimer apex and the exposure of the gp41 HR1 coiled coil. Analysis of HIV-1 variants with increased or reduced sensitivity to 18A suggests that the inhibitor can distinguish distinct conformational states of gp120 in the unliganded Env trimer. The broad-range activity and observed hypersensitivity of resistant mutants to antibody neutralization support further investigation of 18A.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Buy this article
- Purchase on SpringerLink
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout






Similar content being viewed by others
Accession codes
References
Barré-Sinoussi, F. et al. Isolation of a T-lymphotropic retrovirus from a patient at risk for acquired immune deficiency syndrome (AIDS). Science 220, 868–871 (1983).
Gallo, R.C. et al. Frequent detection and isolation of cytopathic retroviruses (HTLV-III) from patients with AIDS and at risk for AIDS. Science 224, 500–503 (1984).
Choe, H. et al. The beta-chemokine receptors CCR3 and CCR5 facilitate infection by primary HIV-1 isolates. Cell 85, 1135–1148 (1996).
Dalgleish, A.G. et al. The CD4 (T4) antigen is an essential component of the receptor for the AIDS retrovirus. Nature 312, 763–767 (1984).
Dragic, T. et al. HIV-1 entry into CD4+ cells is mediated by the chemokine receptor CC–CKR-5. Nature 381, 667–673 (1996).
Feng, Y., Broder, C.C., Kennedy, P.E. & Berger, E.A. HIV-1 entry cofactor: functional cDNA cloning of a seven-transmembrane, G protein–coupled receptor. Science 272, 872–877 (1996).
Furuta, R.A., Wild, C.T., Weng, Y. & Weiss, C.D. Capture of an early fusion-active conformation of HIV-1 gp41. Nat. Struct. Biol. 5, 276–279 (1998).
He, Y. et al. Peptides trap the human immunodeficiency virus type 1 envelope glycoprotein fusion intermediate at two sites. J. Virol. 77, 1666–1671 (2003).
Koshiba, T. & Chan, D.C. The prefusogenic intermediate of HIV-1 gp41 contains exposed C-peptide regions. J. Biol. Chem. 278, 7573–7579 (2003).
Kwon, Y.D. et al. Unliganded HIV-1 gp120 core structures assume the CD4-bound conformation with regulation by quaternary interactions and variable loops. Proc. Natl. Acad. Sci. USA 109, 5663–5668 (2012).
Madani, N. et al. Small-molecule CD4 mimics interact with a highly conserved pocket on HIV-1 gp120. Structure 16, 1689–1701 (2008).
Lin, P.F. et al. A small molecule HIV-1 inhibitor that targets the HIV-1 envelope and inhibits CD4 receptor binding. Proc. Natl. Acad. Sci. USA 100, 11013–11018 (2003).
Si, Z. et al. Small-molecule inhibitors of HIV-1 entry block receptor-induced conformational changes in the viral envelope glycoproteins. Proc. Natl. Acad. Sci. USA 101, 5036–5041 (2004).
LaLonde, J.M. et al. Structure-based design, synthesis, and characterization of dual hotspot small-molecule HIV-1 entry inhibitors. J. Med. Chem. 55, 4382–4396 (2012).
Regueiro-Ren, A. et al. Inhibitors of human immunodeficiency virus type 1 (HIV-1) attachment. 12. Structure-activity relationships associated with 4-fluoro-6-azaindole derivatives leading to the identification of 1-(4-benzoylpiperazin-1-yl)-2-(4-fluoro-7-[1,2,3]triazol-1-yl-1h-pyrrolo[2,3-c]pyridin-3-yl)ethane-1,2-dione (BMS-585248). J. Med. Chem. 56, 1656–1669 (2013).
Schader, S.M. et al. HIV gp120 H375 is unique to HIV-1 subtype CRF01_AE and confers strong resistance to the entry inhibitor BMS-599793, a candidate microbicide drug. Antimicrob. Agents Chemother. 56, 4257–4267 (2012).
Keele, B.F. et al. Identification and characterization of transmitted and early founder virus envelopes in primary HIV-1 infection. Proc. Natl. Acad. Sci. USA 105, 7552–7557 (2008).
Kolchinsky, P., Kiprilov, E., Bartley, P., Rubinstein, R. & Sodroski, J. Loss of a single N-linked glycan allows CD4-independent human immunodeficiency virus type 1 infection by altering the position of the gp120 V1/V2 variable loops. J. Virol. 75, 3435–3443 (2001).
Julien, J.P. et al. Broadly neutralizing antibody PGT121 allosterically modulates CD4 binding via recognition of the HIV-1 gp120 V3 base and multiple surrounding glycans. PLoS Pathog. 9, e1003342 (2013).
Wyatt, R. et al. The antigenic structure of the HIV gp120 envelope glycoprotein. Nature 393, 705–711 (1998).
Xiang, S.H. et al. Epitope mapping and characterization of a novel CD4-induced human monoclonal antibody capable of neutralizing primary HIV-1 strains. Virology 315, 124–134 (2003).
Zhou, T. et al. Structural basis for broad and potent neutralization of HIV-1 by antibody VRC01. Science 329, 811–817 (2010).
Rizzuto, C.D. et al. A conserved HIV gp120 glycoprotein structure involved in chemokine receptor binding. Science 280, 1949–1953 (1998).
Julien, J.P. et al. Crystal structure of a soluble cleaved HIV-1 envelope trimer. Science 1477–1483 (2013).
Haim, H. et al. Contribution of intrinsic reactivity of the HIV-1 envelope glycoproteins to CD4-independent infection and global inhibitor sensitivity. PLoS Pathog. 7, e1002101 (2011).
McGee, K. et al. The selection of low envelope glycoprotein reactivity to soluble CD4 and cold during simian-human immunodeficiency virus infection of rhesus macaques. J. Virol. 88, 21–40 (2014).
Scott, C.F. Jr. et al. Human monoclonal antibody that recognizes the V3 region of human immunodeficiency virus gp120 and neutralizes the human T-lymphotropic virus type IIIMN strain. Proc. Natl. Acad. Sci. USA 87, 8597–8601 (1990).
Haim, H. et al. Modeling virus- and antibody-specific factors to predict human immunodeficiency virus neutralization efficiency. Cell Host Microbe 14, 547–558 (2013).
Kassa, A. et al. Identification of a human immunodeficiency virus type 1 envelope glycoprotein variant resistant to cold inactivation. J. Virol. 83, 4476–4488 (2009).
Kassa, A. et al. Transitions to and from the CD4-bound conformation are modulated by a single-residue change in the human immunodeficiency virus type 1 gp120 inner domain. J. Virol. 83, 8364–8378 (2009).
Doores, K.J. & Burton, D.R. Variable loop glycan dependency of the broad and potent HIV-1-neutralizing antibodies PG9 and PG16. J. Virol. 84, 10510–10521 (2010).
Walker, L.M. et al. Broad and potent neutralizing antibodies from an African donor reveal a new HIV-1 vaccine target. Science 326, 285–289 (2009).
McLellan, J.S. et al. Structure of HIV-1 gp120 V1/V2 domain with broadly neutralizing antibody PG9. Nature 480, 336–343 (2011).
Julien, J.P. et al. Asymmetric recognition of the HIV-1 trimer by broadly neutralizing antibody PG9. Proc. Natl. Acad. Sci. USA 110, 4351–4356 (2013).
Walker, L.M. et al. Broad neutralization coverage of HIV by multiple highly potent antibodies. Nature 477, 466–470 (2011).
Liu, J., Bartesaghi, A., Borgnia, M.J., Sapiro, G. & Subramaniam, S. Molecular architecture of native HIV-1 gp120 trimers. Nature 455, 109–113 (2008).
Decker, J.M. et al. Antigenic conservation and immunogenicity of the HIV coreceptor binding site. J. Exp. Med. 201, 1407–1419 (2005).
Herschhorn, A. et al. An inducible cell-cell fusion system with integrated ability to measure the efficiency and specificity of HIV-1 entry inhibitors. PLoS ONE 6, e26731 (2011).
Pettersen, E.F. et al. UCSF Chimera—a visualization system for exploratory research and analysis. J. Comput. Chem. 25, 1605–1612 (2004).
Herschhorn, A. & Hizi, A. Virtual screening, identification, and biochemical characterization of novel inhibitors of the reverse transcriptase of human immunodeficiency virus type-1. J. Med. Chem. 51, 5702–5713 (2008).
Acknowledgements
We thank Y. McLaughlin and E. Carpelan for manuscript preparation; the AIDS Research and the Reference Reagent Program, Division of AIDS, US National Institute of Allergy and Infectious Diseases, US National Institutes of Health (NIH) for providing reference panels for subtype B and C HIV-1 envelope clones, CFR01_AE.269 HIV-1 envelope clone, psPAX2 plasmid, T20, maraviroc and CEM cells. We also thank B. Keele, G.M. Shaw and the Center for HIV-AIDS Vaccine Immunology Consortium for providing transmitted/founder HIV-1 envelope clones; H.-X. Liao and B.F. Haynes (Duke University Medical Center) for providing the CRF01_AE.CM244 HIV-1 envelope clone; D. Burton (The Scripps Research Institute), J. Robinson (Tulane University) and P.D. Kwong (Vaccine Research Center, NIH) for providing the anti-gp120 monoclonal antibodies; D. Flood, J. Smith and C. Shamu (Institute of Chemistry and Cell Biology, Harvard Medical School) for assistance in the high-throughput screening campaign; and E. Pery, E. Cassol, V. Misra, N. Madani, H. Haim and A.M. Princiotto from Dana-Farber Cancer Institute for helpful discussions and for providing reagents. A.H. was supported by amfAR and is the recipient of an amfAR Mathilde Krim Fellowship in Basic Biomedical Research (108501-53-RKNT). A.F. was supported by Canadian Institutes of Health Research operating grant number 119334 and is the recipient of a Fonds de la recherche en santé du Québec Chercheur Boursier Junior fellowship number 24639 and a Canada Research Chair on Retroviral Entry. Support for this work was also provided by grants from the NIH to J.G.S. (grant numbers AI24755 and GM56550).
Author information
Authors and Affiliations
Contributions
A.H. and J.G.S. conceived and designed the experiments; A.H. and C.G. performed the screening, viral and cell-cell fusion inhibition assays, chimera and mutant Env engineering and antibody binding and inhibition experiments; N.E. performed some of the viability assays; J.R. and A.F. performed some of the Env mutagenesis and experiments assessing CD4-induced conformational changes; and A.H., A.F. and J.G.S. analyzed data and wrote the paper.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Supplementary information
Supplementary Text and Figures
Supplementary Results, Supplementary Tables 1–5 and Supplementary Figures 1–15. (PDF 6450 kb)
Rights and permissions
About this article
Cite this article
Herschhorn, A., Gu, C., Espy, N. et al. A broad HIV-1 inhibitor blocks envelope glycoprotein transitions critical for entry. Nat Chem Biol 10, 845–852 (2014). https://doi.org/10.1038/nchembio.1623
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nchembio.1623