FIGURE 2.

Representative raw data of packaging events of various terminases using an optical tweezers assay. A schematic depicting the assay is shown in the upper right panel. Beads were held in two optical traps: one bead holds the viral procapsid, and the other holds the DNA/terminase complex. Packaging traces for all mutants shown end with a stall. Packaging was initiated when the beads are brought closer together and the DNA/terminase complex binds to the procapsids. A 5-pN force clamp was utilized to track packaging for long distances.