FIG. 6.
SDS-PAGE of structural proteins of wt and PI viruses. Purified [35S]methionine-labeled virions of wt SA11 and PI-SA11-B/135 at a concentration of 2 × 1011 particles per ml were treated with trypsin at the concentrations shown (in micrograms per milliliter) at 37°C for 30 min. Equal volumes of samples (2 × 109 particles) were loaded into wells of an 8% SDS-polyacrylamide gel. After electrophoresis, gels were prepared for fluorography and exposed to film. Viral proteins are labeled on the left, and positions of molecular size markers are shown on the right (in kilodaltons).