Host Cofactors and Pharmacologic Ligands Share an Essential Interface in HIV-1 Capsid That Is Lost upon Disassembly
Figure 9
Inhibition of HIV-1 infection by BI-2, PF74 and PF74 derivatives.
(A) Titration of PF74 or indicated derivatives onto HeLa cells infected with VSV-G pseudotyped GFP-encoding HIV-1 vector. For each titration, infectivity is normalised to the level in the absence of inhibitor (100%). (B) Correlation between the IC90 values derived from (A) and the Kd values for purified hexameric capsid as calculated by ITC (Figure 8). The values are highly correlative with a Pearson correlation coefficient of 0.9928 and a P-value of 0.0007. (C) Titration of PF74 or BI-2 onto cells infected with VSV-G pseudotyped GFP-encoding HIV-1 vectors, normalized as in (A). (D) Data from (C) but with infectivity plotted against drug concentration divided by affinity to hexamer as calculated by ITC. (E) Titres of VSV-G pseudotyped GFP-encoding HIV-1 vectors 48 h post-infection and levels of reverse transcription (RT) 4 h post-infection under conditions of PF74 inhibition. For both measures, data are normalized to the values obtained in the absence of inhibitor. (F) Data from (E), except plotted against the calculated level of CA occupancy by PF74. The occupancy was calculated assuming that there are 1500 free sites per capsid and that number of free sites = 1500(1−([PF74]/Kd[PF74])) (G) Infectivity and reverse transcription in cells infected in the presence of PF74 (wash) or when removed after four hours (wash out). Reverse transcription was then measured after a further 4 h, while infectivity was determined 48 h post-infection. (H) Levels of reverse transcription 4 h post-infection of HeLa cells in the presence of PF74 and its derivatives at 20× IC9o drug concentrations.