title: Plasmodium falciparum normocyte binding protein (PfNBP-1) peptides bind specifically to human erythrocytes.
abstract: Plasmodium falciparum normocyte binding protein-1 (PfNBP-1), a Plasmodium vivax RBP-1 orthologue is expressed in the apical merozoite area. PfNBP-1 binds directly to human erythrocyte membrane in a sialic acid-dependent but trypsin-resistant way. Erythrocyte binding assays were done with synthetic peptides covering the sequence reported as PfNBP-1. Two specific erythrocyte high activity binding peptides were found: 101VFINDLDTYQYEYFYEWNQ(120), peptide 26332, and 181NTKETYLKELNKKKMLQNKK(200), peptide 26336. These two peptides' binding was saturable and presenting nanomolar affinity constants. The critical binding residues (those residues underlined and highlighted in bold) were determined by competition assays with glycine-scan analogue peptides. These peptides were able to block merozoite in vitro invasion of erythrocytes.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D002738:Chloroquine / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D002918:Chymotrypsin / Q000378:metabolism / Q000494:pharmacology; D003432:Cross-Linking Reagents / Q000737:chemistry; D004533:Egtazic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000737:chemistry / Q000378:metabolism* / Q000469:parasitology; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D009439:Neuraminidase / Q000378:metabolism / Q000494:pharmacology; D021261:Parasitic Sensitivity Tests; D010455:Peptides / Q000138:chemical synthesis / Q000378:metabolism*; D010963:Plasmodium falciparum / Q000502:physiology; D011485:Protein Binding; D015800:Protozoan Proteins / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014357:Trypsin / Q000378:metabolism / Q000494:pharmacology
chemical_list: D003432:Cross-Linking Reagents; D008565:Membrane Proteins; D010455:Peptides; D015800:Protozoan Proteins; C443160:normocyte binding protein 1, plasmodium falciparum; D004533:Egtazic Acid; D002738:Chloroquine; D009439:Neuraminidase; D002918:Chymotrypsin; D014357:Trypsin