FIG. 4.

Effect of cholesterol depletion on the ultrastructure of DHBV particles and L topology. (A) Viral particles were immunocaptured to beads from viremic serum, treated with different CD concentrations, and processed for ultrastructural analysis by TEM. The lower magnifications show the decoration of beads with viral particles. The ultrastructure of single viral particles is shown at high magnification in the subpanels. (B) Dual topology of L protein before and after cholesterol depletion of viral particles was determined by protease protection assay. Trypsin-mediated proteolysis of L protein in the membranes of CD- and mock-treated DHBV particles was monitored by immunoblotting before and after addition of NP-40.