FIGURE 3.

Effect of gp2 concentration on the gp2-procapsid interaction and on DNA packaging. A, dose-dependent effect of gp2 on procapsid binding. Procapsids (proc; 10 nm) were incubated in the absence (−) or in the presence of increasing doses of gp2 for 1 h followed by 10 min incubation with cobalt beads. The presence of procapsids in the bead fraction was checked by Western blot using anti-SPP1 and anti-gp2 antibodies. B, dose-dependent effect of gp2 on DNA packaging. DNA-packaging reactions in vitro were carried out for 1 h as described under “Experimental Procedures” using 10 nm procapsids and the gp2 concentrations indicated in the figure. The amount of packaged DNA was checked in a 0.8% agarose gel.