title: Processing of the Plasmodium falciparum major merozoite surface protein-1: identification of a 33-kilodalton secondary processing product which is shed prior to erythrocyte invasion.
abstract: We have previously shown that only a single 19-kDa fragment of the Plasmodium falciparum major merozoite surface protein (MSP1) is carried with an invading merozoite into the infected red cell. This fragment (MSP1(19] is derived from the C-terminal membrane-bound end of a major product, MSP1(42), of the primary stage of MSP1 proteolytic processing. Using a monoclonal antibody mapped to an epitope within the N-terminal region of MSP1(42), we have shown that a soluble 33-kDa polypeptide (MSP1(33) corresponding to the N-terminal region of MSP1(42) is shed into culture supernatants during merozoite release and erythrocyte invasion. These observations provide further evidence that the secondary processing of MSP1(42) involves a highly site-specific proteolytic activity.
authors.affiliation: National Institute for Medical Research, Mill Hill, London, U.K.
authors.forename: M J
authors.initials: MJ
authors.lastname: Blackman
authors.forename: H
authors.initials: H
authors.lastname: Whittle
authors.forename: A A
authors.initials: AA
authors.lastname: Holder
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000953:Antigens, Protozoan / Q000235:genetics; D000954:Antigens, Surface / Q000235:genetics; D000939:Epitopes / Q000235:genetics; D004912:Erythrocytes / Q000469:parasitology; D020066:Merozoite Surface Protein 1; D008970:Molecular Weight; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D010963:Plasmodium falciparum / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011498:Protein Precursors / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D015800:Protozoan Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D000953:Antigens, Protozoan; D000954:Antigens, Surface; D000939:Epitopes; D020066:Merozoite Surface Protein 1; D010446:Peptide Fragments; D011498:Protein Precursors; D015800:Protozoan Proteins