title: Homologous genes encode two distinct histidine-rich proteins in a cloned isolate of Plasmodium falciparum.
abstract: Two genes encoding distinct histidine-rich proteins in a Plasmodium falciparum clone exhibit high levels of homology, suggesting they have originated by duplication and divergence from a common ancestral sequence. Both genes have a similar interrupted structure and an exon that encodes closely related tandem repeats of very high histidine and alanine content. The most common repeat encoded by one gene, the hexapeptide Ala-His-His-Ala-Ala-Asp, differs in the sixth position from the most common repeat encoded by the other gene, the hexapeptide Ala-His-His-Ala-Ala-Asn. The divergence of the repeat domains is greater than that of the flanking regions, which exhibit 85-90% homology, including untranslated sequences. This suggests the tandem repeats are relatively labile elements within the genome that may provide the parasite with a means of rapid evolutionary change.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004262:DNA Restriction Enzymes; D005796:Genes; D006023:Glycoproteins / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D010963:Plasmodium falciparum / Q000235:genetics* / Q000302:isolation & purification; D011506:Proteins / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D000099053:Histidine-Rich Glycoprotein
chemical_list: D006023:Glycoproteins; D011506:Proteins; D000099053:Histidine-Rich Glycoprotein; D004262:DNA Restriction Enzymes