FIG. 5.

Size determination of membrane-bound Gag complexes. Membrane-bound Gag proteins were first isolated by membrane flotation and extracted with 1% Triton X-100 at 37°C for 10 min to deplete membranes. Membrane-free Gag proteins were further centrifuged at 100,000 × g for 1 h at 4°C. The resultant supernatants (termed S100) and pellets (termed P100) were assayed by Western blot using anti-p24 (capsid) antibodies. Relative quantities of the M368A, L20K-M368A, and wild-type Gag proteins in the P100 fraction were assessed by using the NIH Image program, and the results are shown in the graph. WT, wild type.