Structure of the knob protein (KP) gene of Plasmodium falciparum.

We have determined the nucleotide sequence of the gene encoding the knob protein (KP) of Plasmodium falciparum (FCR-3/Gambia). The gene is interrupted by an intron which contains 34 imperfect tandemly repeated ATTTT sequences. The first exon encodes 33 amino acids with a hydrophobic core typical of signal peptides. The second exon has an open translational reading frame for 597 amino acids. The deduced protein sequence indicates that KP has multiple structural domains; unlike the N-terminal histidine-rich domain which we described previously, the C-terminal half is rich in lysine residues. Consistent with the apparent association of KP with the cytoplasmic surface of the host erythrocyte membrane, the protein is highly charged and hydrophilic.