FIG 3.

Kinetics of SDS-mediated hexon dissociation and reassociation. (A) To test the kinetics of SDS sensitivity, purified hexon was incubated at pH 4.4 for 30 min and then exposed to PSB for the indicated time periods. Coomassie blue-stained SDS-PAGE gels of unboiled samples show detectable hexon dissociation 5 min after the addition of PSB and a complete effect after 20 min, indicating a gradual SDS effect. (B) To test the kinetics of pH sensitivity, purified hexon was incubated either at pH 7.4 for 30 min or at pH 4.4 for 5 min, followed by 20 min of incubation with PSB and SDS-PAGE of unboiled samples. Hexon sensitivity to dissociation was clearly established within 5 min. (C) To test the kinetics of reassociation, purified hexon was incubated at pH 4.4 for 5 min and neutralized for the indicated time periods, followed by 20 min of incubation with PSB and SDS-PAGE of unboiled samples. Full reassociation occurred within 30 to 60 min.