Sequences of the Plasmodium falciparum cytoadherence-linked asexual protein 9 implicated in malaria parasite invasion to erythrocytes.

In this study, we synthesized the complete sequence of the CLAG-9 protein as 67 20-mer-long non-overlapped peptides and assessed their ability to bind to erythrocytes in receptor-ligand assays. Twenty CLAG-9 peptides were found to have specific high-affinity binding ability to erythrocytes (thereby named as HABPs), with nanomolar dissociation constants. CLAG-9 HABPs interacted with different erythrocyte surface receptors having apparent molecular weights of 85, 63 and 34 kDa.

Identification of Plasmodium falciparum RhopH3 protein peptides that specifically bind to erythrocytes and inhibit merozoite invasion.

The identification of sequences involved in binding to erythrocytes is an important step for understanding the molecular basis of merozoite-erythrocyte interactions that take place during invasion of the Plasmodium falciparum malaria parasite into host cells. Several molecules located in the apical organelles (micronemes, rhoptry, dense granules) of the invasive-stage parasite are essential for erythrocyte recognition, invasion, and establishment of the nascent parasitophorous vacuole. Particularly, it has been demonstrated that rhoptry proteins play an important role in binding to erythrocyte surface receptors, among which is the PfRhopH3 protein, which triggers important immune responses in patients from endemic regions.

Studies of Plasmodium falciparum rhoptry-associated membrane antigen (RAMA) protein peptides specifically binding to human RBC.

Plasmodium falciparum rhoptry-associated membrane antigen (RAMA) peptides used in normal red blood cell (RBC) binding assays revealed that peptides 33426 (79NINILSSVHRKGRILYDSF97) and 33460 (777HKKREKSISPHSYQKVSTKVQ797) bound with high activity, presenting nanomolar affinity constants. Such high binding activity peptides (HABPs) displayed helicoid and random coil structures as determined by circular dichroism. HABPs inhibited P.