Figure 3: P. knowlesi invasion ligands PkDBPβ and PkDBPγ bind to Neu5Gc-sialylated receptors.
From: Ancient human sialic acid variant restricts an emerging zoonotic malaria parasite
(a) Left panel—PkDBPα-COMP binds to DARC on untreated (U), neuraminidase-treated (N) and trypsin-treated (T) macaque RBCs, but not chymotrypsin-treated (C) macaque RBCs as seen in a protein overlay. Right panel—α-DARC western blot confirms that the PkDBPα receptor on macaque RBCs is DARC (highlighted by the bracket). (b) Binding of PkDBPβ-COMP and PkDBPγ-COMP to untreated and protease-treated macaque RBCs, but not to neuraminidase-treated macaque RBCs. GST-COMP does not bind to macaque RBCs. Data are representative of at least four independent experiments. (c) PkDBPβ-COMP (red) and PkDBPγ-COMP (blue) bind to untreated (solid trace) PtCMAH cRBCs, as to macaque RBCs, but not to pLVX cRBCs, like human RBCs as determined by a flow cytometry-based assay. Binding to neuraminidase-treated (dashed trace) PtCMAH cRBCs and macaque RBCs is markedly decreased. COMP protein (black) does not bind to any cell type. The assay was performed twice, in triplicate; representative traces are shown.
