Diaz-Griffero Lab
Anti-retroviral Drugs
BI-2
The recently discovered small-molecule BI-2 potently blocks HIV-1 infection. BI-2 binds to the N-terminal domain of HIV-1 capsid. BI-2 utilizes the same capsid pocket used by the small molecule PF74. Although both drugs bind to the same pocket, it has been proposed that BI-2 uses a different mechanism to block HIV-1 infection when compared to PF74. Our work demonstrated that BI-2 destabilizes the HIV-1 core during infection, and prevents the binding of the cellular factor CPSF6 to the HIV-1 core. Overall we found BI-2 to use a similar mechanism to the one used by PF74 to block HIV-1 infection.
FIgure 1. BI-2 destabilizes the HIV-1 Core during infection.
Figure 2. BI-2 blocks HIV-1 and SIV mac infection.
Figure 3. BI-2 prevents the binding of the cellular factor CPSF6 to HIV-1 CA-NC complexes.
Fricke T, Buffone C, Opp S, Valle-Casuso J, Diaz-Griffero F. BI-2 destabilizes HIV-1 cores during infection and Prevents Binding of CPSF6 to the HIV-1 Capsid. Retrovirology. 2014 Dec 11;11:120. doi: 10.1186/s12977-014-0120-x. PubMed PMID: 25496772; PubMed Central PMCID: PMC4271331.
Fricke T, Brandariz-Nuñez A, Wang X, Smith AB 3rd, Diaz-Griffero F. Human cytosolic extracts stabilize the HIV-1 core. J Virol. 2013 Oct;87(19):10587-97. doi: 10.1128/JVI.01705-13. Epub 2013 Jul 24. PubMed PMID: 23885082; PubMed Central PMCID: PMC3807412.
PF74
Figure 1. Chemical structure of PF74.
We found through biochemical experiments that PF-3450074 (PF74), a drug that inhibits HIV-1 infection, as well as host proteins cleavage and polyadenylation specific factor 6 (CPSF6) and nucleoporin 153 kDa (NUP153), bind to the CA hexamer with at least 10-fold higher affinities compared with nonassembled CA or isolated CA domains. The crystal structure of PF74 in complex with the CA hexamer reveals that PF74 binds in a preformed pocket encompassing the NTD–CTD interface, suggesting that the principal inhibitory target of PF74 is the assembled capsid. Likewise, CPSF6 binds in the same pocket. Given that the NTD–CTD interface is a specific molecular signature of assembled hexamers in the capsid, binding of NUP153 at this site suggests that key features of capsid architecture remain intact upon delivery of the preintegration complex to the nucleus
Figure 2. Structure of PF74 in complex with the HIV-1 CA hexamer. (A) Top view of the hexamer, with each subunit in a different color and the bound PF74 in white. (B) Unbiased mFo-DFc density at 3σ (magenta mesh) clearly defines the bound compound at the NTD–CTD interface. NTD is in cyan, and CTD is in green.
Figure 3. The HIV-1 inhibitor PF74 increases the stability of HIV-1 CA-NC complexes.
Bhattacharya A, Alam SL, Fricke T, Zadrozny K, Sedzicki J, Taylor AB, Demeler B, Pornillos O, Ganser-Pornillos BK, Diaz-Griffero F, Ivanov DN, Yeager M. Structural basis of HIV-1 capsid recognition by PF74 and CPSF6. Proc Natl Acad Sci U S A. 2014 Dec 30;111(52):18625-30. doi: 10.1073/pnas.1419945112. Epub 2014 Dec 17. PubMed PMID: 25518861; PubMed Central PMCID: PMC4284599.
Fricke T, Buffone C, Opp S, Valle-Casuso J, Diaz-Griffero F. BI-2 destabilizes HIV-1 cores during infection and Prevents Binding of CPSF6 to the HIV-1 Capsid. Retrovirology. 2014 Dec 11;11:120. doi: 10.1186/s12977-014-0120-x. PubMed PMID: 25496772; PubMed Central PMCID: PMC4271331.
Fricke T, Brandariz-Nuñez A, Wang X, Smith AB 3rd, Diaz-Griffero F. Human cytosolic extracts stabilize the HIV-1 core. J Virol. 2013 Oct;87(19):10587-97. doi: 10.1128/JVI.01705-13. Epub 2013 Jul 24. PubMed PMID: 23885082; PubMed Central PMCID: PMC3807412.
3G11
Figure 1. Chemical structure of 3G11.
The small-molecule 6-(tert-butyl)-4-phenyl-4-(trifluoromethyl)-1H,3H-1,3,5-triazin-2-one (3G11) inhibits HIV-1 replication in the human T cell line MT-2. Here, we showed that 3G11 specifically and potently blocks HIV-1 infection. By contrast, 3G11 did not block other retroviruses such as HIV-2, simian immunodeficiency virus (SIVmac), bovine immunodeficiency virus, feline immunodeficiency virus, equine infectious anemia virus, N-tropic murine leukemia virus, B-tropic murine leukemia virus, and Moloney murine leukemia virus.
Figure 2. 3G11 is a specific inhibitor of HIV-1 infection.
Figure 3. 3G11 binds to the HIV-1 capsid. (a) CA-NTD residues perturbed by 3G11 binding identified by NMR spectroscopy. Spectrum of 120 μm CA-NTD alone in red, NMR spectrum of 120 μm CA-NTD + 600 μm 3G11 drug (1:5 ratio) in green. Overlapping peaks appear black. (b) Model of the 3G11/HIV-1 CA-NTD complex. Residues whose NMR signals are most affected by 3G11 binding are highlighted in yellow. (c) Crystal structure of the BD3/HIV-1 CA-NTD complex (PDB ID: 4E91) reveals that the compound binds in a deep interior pocket sandwiched between CA-NTD helices (left panel). 3G11 can be accommodated in the BD3-binding pocket of HIV-1 CA-NTD (middle panel). Similarly, 3G11 docks into the HIV-2 CA-NTD (right panel). (d) Model of the 3G11-bound CA hexamer viewed from the interior of the core particle. The 3G11- and BD3-binding site is accessible from the core interior and binding of the compound is not expected to generate steric clashes in the assembled core structure.
Opp S, Fricke T, Shepard C, Kovalskyy D, Bhattacharya A, Herkules F, Ivanov DN, Kim B, Valle-Casuso J, Diaz-Griffero F. The small-molecule 3G11 inhibits HIV-1 reverse transcription. Chem Biol Drug Des. 2016 Oct; DOI:10.1111/cbdd.12886