FIG. 5.

Effect of 3(2H)-isoflavene on sucrose gradient sedimentation profiles of PV2 Sabin (Sab), R2/01, and D6/01 variants. (A) Binding of purified [³⁵S]methionine-labeled viruses to HeLa cells was synchronized by 1 h of incubation at 4°C in the presence or absence of the compound (20 μM). After removal of unbound virus, cells were incubated in the presence or absence of the compound at 37°C for the indicated times and then lysed. Cell-associated radiolabeled viral particles were centrifuged through a 15 to 30% sucrose gradient. Fractions were collected, and radioactivity was measured in a beta-scintillation counter. The percentages of mature 160S and 135S viral particles are indicated. WIN 51711 was used in the assay as an inhibitor of uncoating. (B) [³⁵S]methionine-labeled variant D6/01 virions were incubated with or without compound at 37°C without cells for the indicated times. Virus-associated radioactivity was analyzed on a 15 to 30% sucrose gradient, as specified above. The percentages of the 160S, 135S, and 80S viral particles are indicated.