In vitro DNA packaging. (A) Comparison of packaging at different temperatures. Lanes from left to right: input DNA (no DNase), negative control with no added capsids, negative control with no added large terminase, packaging reactions at different temperatures. (B) Packaging time course. Lanes from left to right: size marker, input DNA (no DNase), negative control with no added capsids, negative control with no added ATP, and packaging for 15, 30, 45, and 60 min. (C) Comparison of the ability of the procapsid and expanded capsid to protect DNA from DNase digestion. Lanes from left to right: size marker, input DNA (no DNase), and packaging reactions with no added large terminase (control), with added large terminase at 50 °C and 20 °C, and with ATP substituted by ATPγS (γ).