The SV40 Late Protein VP4 Is a Viroporin that Forms Pores to Disrupt Membranes for Viral Release
Figure 4
RBC surface proteins are not required for VP4-mediated hemolysis.
(A) RBCs (lane 1) were pretreated with trypsin and proteinase K (pRBCs, lane 2) to remove surface proteins. Membrane fractions after hypotonic lysis were resolved by reducing SDS-PAGE and proteins were visualized by coomassie blue staining. (B) GST-VP4 was mixed with untreated or protease treated RBCs. After incubation for 30 min at 37°C, hemoglobin release was measured by the A414 of the supernatant after centrifugation to remove unlysed cells. The error bars represent the standard deviation from two independent experiments performed in triplicate.