title: Entamoeba histolytica: computer-assisted modeling of phosphofructokinase for the prediction of broad-spectrum antiparasitic agents.
abstract: Pyrophosphate-dependent phosphofructokinase (PPi-PFK) is the rate-limiting glycolytic enzyme found in the pathogenic protists Entamoeba histolytica, Giardia lamblia, Toxoplasma gondii, Trichomonas vaginalis, and Naegleria fowleri. The enzyme differs significantly from ATP-dependent phosphofructokinases found in humans and as such represents an important drug target. Current therapy for infections caused by these pathogens is inadequate, especially for children, pregnant women, and the immune compromised. The development of more selective, safer agents in imperative, as parasitic infections are currently a significant health threat worldwide and will likely become increasingly common agents of disease in the future. For the purpose of designing drugs to treat parasitic infections, we have constructed a model of PPi-PFK from E. histolytica based on the three-dimensional structure of the ATP-dependent PFK from Bacillus stearothermophilus. The model was used with the computer program Dock 3.5 (University of California, San Francisco) to predict the binding of pyrophosphate and selected bisphosphonates to the enzyme. The predicted drug-enzyme interactions suggested that two of these compounds would be competitive inhibitors of pyrophosphate. These drugs were tested against E. histolytica and inhibited the growth of amebae in vitro. This class of compounds may have broad-spectrum antiparasitic activity and, in the future, may facilitate the treatment of serious parasitic infections.
authors.affiliation: Department of Pediatrics, University of Utah Health Sciences Center, Salt Lake City 84132, USA. cbyington@med.utah.edu
authors.forename: C L
authors.initials: CL
authors.lastname: Byington
authors.forename: R L
authors.initials: RL
authors.lastname: Dunbrack
authors.forename: F G
authors.initials: FG
authors.lastname: Whitby
authors.forename: F E
authors.initials: FE
authors.lastname: Cohen
authors.forename: N
authors.initials: N
authors.lastname: Agabian
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000981:Antiprotozoal Agents / Q000378:metabolism*; D001665:Binding Sites; D003198:Computer Simulation; D011756:Diphosphates / Q000378:metabolism*; D004164:Diphosphonates / Q000378:metabolism*; D015195:Drug Design; D004353:Drug Evaluation, Preclinical; D004748:Entamoeba histolytica / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D012968:Etidronic Acid / Q000378:metabolism*; D007093:Imidazoles / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010732:Phosphofructokinase-1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D000077211:Zoledronic Acid
chemical_list: D000981:Antiprotozoal Agents; D011756:Diphosphates; D004164:Diphosphonates; D007093:Imidazoles; D000077211:Zoledronic Acid; D010732:Phosphofructokinase-1; D012968:Etidronic Acid