Fig. 1.

Characterization of O-glycosylated MMV glycoproteins by jacalin chromatography and protein sequencing. (a) Schematic of the jacalin-affinity chromatography and tandem MS approach. Solubilized microvilli were loaded onto the jacalin column and eluted with Gal. An aliquot of the 800 mM Gal eluate was fractionated by electrophoresis and silver-stained. The remaining sample was subjected to proteomic analysis (Table 1). (b) Predicted structure and glycosylation sites of AgAPN1. Black rectangle, predicted signal sequence; vertically hatched rectangles, peptidase M1 family domains; checkered box, antibody epitopes; stippled box, gluzincin motif; cross-hatched box, C-terminal GPI anchor. Predicted glycosylation sites are as follows: filled triangles, O-linked glycan,; filled diamonds, GAG modification site. Amino acid position numbers for the corresponding sites are as indicated. The diagram is drawn to scale. Note that AgAPN1 is predicted to have multiple O-glycan and GAG modification sites that are ligands for jacalin and, presumably, ookinete micronemal proteins, respectively (see text for details).