1qs8
CRYSTAL STRUCTURE OF THE P. VIVAX ASPARTIC PROTEINASE PLASMEPSIN COMPLEXED WITH THE INHIBITOR PEPSTATIN A
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OverviewOverview
The malarial aspartic proteinases (plasmepsins) have been discovered in, several species of Plasmodium, including all four of the human malarial, pathogens. In P.falciparum, plasmepsins I, II, IV and HAP have been, directly implicated in hemoglobin degradation during malaria infection, and are now considered targets for anti-malarial drug design. The, plasmepsins are produced from inactive zymogens, proplasmepsins, having, unusually long N-terminal prosegments of more than 120 amino acids., Structural and biochemical evidence suggests that the conversion process, of proplasmepsins to plasmepsins differs substantially from the gastric, and plant aspartic proteinases. Instead of blocking substrate access to a, pre-formed active site, the prosegment enforces a conformation in which, proplasmepsin cannot form a functional active site. We have determined, crystal structures of plasmepsin and proplasmepsin from P.vivax. The, three-dimensional structure of P.vivax plasmepsin is typical of the, monomeric aspartic proteinases, and the structure of P.vivax proplasmepsin, is similar to that of P.falciparum proplasmepsin II. A dramatic refolding, of the mature N terminus and a large (18 degrees ) reorientation of the, N-domain between P.vivax proplasmepsin and plasmepsin results in a severe, distortion of the active site region of the zymogen relative to that of, the mature enzyme. The present structures confirm that the mode of, inactivation observed originally in P.falciparum proplasmepsin II, i.e. an, incompletely formed active site, is a true structural feature and likely, represents the general mode of inactivation of the related proplasmepsins.
About this StructureAbout this Structure
1QS8 is a Single protein structure of sequence from Plasmodium vivax with ACT as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Structural insights into the activation of P. vivax plasmepsin., Bernstein NK, Cherney MM, Yowell CA, Dame JB, James MN, J Mol Biol. 2003 Jun 6;329(3):505-24. PMID:12767832
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