Four plasmepsins are active in the Plasmodium falciparum food vacuole, including a protease with an active-site histidine

Proc Natl Acad Sci U S A. 2002 Jan 22;99(2):990-5. doi: 10.1073/pnas.022630099. Epub 2002 Jan 8.

Abstract

Hemoglobin degradation is a metabolic process that is central to the growth and maturation of the malaria parasite Plasmodium falciparum. Two aspartic proteases that initiate degradation, plasmepsins (PMs) I and II, have been identified and extensively characterized. Eight additional PM genes are present in the P. falciparum genome. To better understand the enzymology of hemoglobin degradation, it is necessary to determine which of these genes are expressed when hemoglobin degradation is occurring, which encode active enzymes, and which gene products are found in the food vacuole where catabolism takes place. Our genome-wide analysis reveals that PM I, II, and IV and histo-aspartic protease encode hemoglobin-degrading food vacuole proteases. Despite having a histidine in place of one of the catalytic aspartic acids conserved in other aspartic proteases, histo-aspartic protease is an active hydrolase.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Aspartic Acid Endopeptidases / genetics
  • Aspartic Acid Endopeptidases / metabolism*
  • Erythrocytes / parasitology
  • Hemoglobins / metabolism
  • Humans
  • Plasmodium falciparum / enzymology*
  • Plasmodium falciparum / genetics
  • Plasmodium falciparum / pathogenicity
  • Protozoan Proteins
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Vacuoles / enzymology

Substances

  • Hemoglobins
  • Protozoan Proteins
  • Recombinant Proteins
  • Aspartic Acid Endopeptidases
  • plasmepsin
  • plasmepsin II