Plasmodium falciparum Cysteine-Rich Protective Antigen (PfCyRPA) is a 42.8 kDa protein of 362 residues with a predicted N-terminal secretion signal. It is part of a multi-protein complex including the PfRH5-interacting protein PfRipr and the reticulocyte binding-like homologous protein PfRH5, which binds to the erythrocyte receptor basigin. PfRH5, PfCyRPA, and PfRipr colocalize during parasite invasion at the junction between merozoites and erythrocytes. The complex seems to be required both for triggering Ca2+ release and establishment of tight junctions. PfCyRPA adopts a 6-bladed beta-propeller structure with similarity to the classic sialidase fold, but it has no sialidase activity and fulfills a purely non-enzymatic function. Each blade of the propeller is constructed by a four-stranded anti-parallel beta-sheet [1].

1: Structure of the malaria vaccine candidate antigen CyRPA and its complex with a parasite invasion inhibitory antibody. Favuzza P, Guffart E, Tamborrini M, Scherer B, Dreyer AM, Rufer AC, Erny J, Hoernschemeyer J, Thoma R, Schmid G, Gsell B, Lamelas A, Benz J, Joseph C, Matile H, Pluschke G, Rudolph MG; Elife. 2017; [Epub ahead of print] PMID:28195038