Figure 2.

Native agarose gel electrophoresis (AGE) analysis of the interaction of phage T4 with methylene blue (MB). Phage T4 was prepared and partially purified as previously described for the gated loading of ethidium and bleomycin [55]. Then, T4 was incubated with MB at 54 °C for 1.0 h and subjected to horizontal AGE, as described in [55]. (a) The gel was photographed after staining with GelStar for 3.0 h [55]. (b) The same gel was photographed after the expulsion of packaged DNA by incubation for 18.0 h with 0.002 M EDTA, pH 7.4, at room temperature (22 ± 3 °C). The concentration of MB (mM) is indicated at the top of a lane. The arrowheads indicate the origins of electrophoresis; the arrows indicate the direction of electrophoresis. A phage T3 standard was included (lane labeled T3). Some DNA was spontaneously expelled from both T3 and T4, as indicated by the horizontal lines labeled D at the right.