Fig. 3.

PfSUB1-mediated proteolytic processing of the Wellcome-type MSP1 is ordered.A. Typical time-course of digestion of native T9/94 P. falciparum-derived MSP1. Saponin-permeabilized T9/94 schizonts were incubated at 37°C in the presence of rPfSUB1. Samples taken at intervals were analysed by Western blot, probing with either the MSP1₈₃-specific mAb 89.1 (left-hand side), or a MSP1₄₂-specific polyclonal antibody (right-hand side). For both blots the MSP1 precursor is indicated with a black arrow, processing intermediates are marked with an open arrow, or closed square-head lollipop, while terminal processing products are marked with an open round or square-head lollipop. No processing was observed in the absence of added rPfSUB1 (not shown).B. Schematic of the order of Wellcome-type MSP1 primary processing, determined from the digestion assay shown in A. Individual processed species are marked with arrow or lollipop symbols to aid comparison with the corresponding bands on the blots.