Design and synthesis of potent inhibitors of plasmepsin I and II: X-ray crystal structure of inhibitor in complex with plasmepsin II

J Med Chem. 2005 Jun 30;48(13):4400-9. doi: 10.1021/jm040884n.

Abstract

New and potent inhibitors of the malarial aspartic proteases plasmepsin (Plm) I and II, from the deadliest malaria parasite Plasmodium falciparum, have been synthesized utilizing Suzuki coupling reactions on previously synthesized bromobenzyloxy-substituted statine-like inhibitors. The enzyme inhibition activity has been improved up to eight times by identifying P1 substituents that effectively bind to the continuous S1-S3 crevice of Plasmepsin I and II. By replacement of the bromo atom in the P1 p-bromobenzyloxy-substituted inhibitors with different aryl substituents, several inhibitors exhibiting K(i) values in the low nanomolar range for both Plm I and II have been identified. Some of these inhibitors are also effective in attenuating parasite growth in red blood cells, with the best inhibitors, compounds 2 and 4, displaying 70% and 83% inhibition, respectively, at a concentration of 5 microM. The design was partially guided by the X-ray crystal structure disclosed herein of the previously synthesized inhibitor 1 in complex with plasmepsin II.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antiprotozoal Agents / chemical synthesis*
  • Antiprotozoal Agents / chemistry
  • Antiprotozoal Agents / pharmacology*
  • Aspartic Acid Endopeptidases / antagonists & inhibitors*
  • Aspartic Acid Endopeptidases / chemistry*
  • Crystallography, X-Ray
  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Molecular Conformation
  • Plasmodium falciparum / drug effects
  • Plasmodium falciparum / enzymology*
  • Protozoan Proteins
  • Structure-Activity Relationship

Substances

  • Antiprotozoal Agents
  • Protozoan Proteins
  • Aspartic Acid Endopeptidases
  • plasmepsin
  • plasmepsin II