Synopsis.
The malaria parasite Plasmodium falciparum , exports hundreds of proteins into the red blood cells (RBC) it infects to help it grow and replicate. Most exported proteins possess a five amino acid barcode that acts as a proteolytic cleavage site and licenses these proteins for export into the RBC compartment by protein translocating gateways surrounding the parasite. We report here that the conserved fifth amino acid position of the barcode plays an important role in the proteolytic maturation of exported protein and, together with the downstream flexible spacer region preceding the folded region of the exported protein, are important for efficient transport into the RBC viaPlasmodium Translocon of Exported Proteins (PTEX).