Identification and characterization of small molecule inhibitors of Plasmodium falciparum dihydroorotate dehydrogenase.
Plasmodium falciparum causes the most deadly form of malaria and accounts for over one million deaths annually. The malaria parasite is unable to salvage pyrimidines and relies on de novo biosynthesis for survival. Dihydroorotate dehydrogenase (DHOD), a mitochondrially localized flavoenzyme, catalyzes the rate-limiting step of this pathway and is therefore an attractive antimalarial chemotherapeutic target. Using a target-based high throughput screen, we have identified a series of potent, species-specific inhibitors of P. falciparum DHOD (pfDHOD) that are also efficacious against three cultured strains (3D7, HB3, and Dd2) of P. falciparum. The primary antimalarial mechanism of action of these compounds was confirmed to be inhibition of pfDHOD through a secondary assay with transgenic malaria parasites, and the structural basis for enzyme inhibition was explored through in silico structure-based docking and site-directed mutagenesis. Compound-mediated cytotoxicity was not observed with human dermal fibroblasts or renal epithelial cells. These data validate pfDHOD as an antimalarial drug target and provide chemical scaffolds with which to begin medicinal chemistry efforts.
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Vishal
V
Patel
Michael
M
Booker
Martin
M
Kramer
Leila
L
Ross
Cassandra A
CA
Celatka
Leah M
LM
Kennedy
Jeffrey D
JD
Dvorin
Manoj T
MT
Duraisingh
Piotr
P
Sliz
Dyann F
DF
Wirth
Jon
J
Clardy
D000818:Animals; D000962:Antimalarials / Q000494:pharmacology; D002626:Chemistry, Pharmaceutical / Q000379:methods; D000090722:Dihydroorotate Dehydrogenase; D015195:Drug Design; D004353:Drug Evaluation, Preclinical; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D020128:Inhibitory Concentration 50; D008288:Malaria / Q000188:drug therapy; D008956:Models, Chemical; D016297:Mutagenesis, Site-Directed; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000037:antagonists & inhibitors* / Q000737:chemistry*; D010963:Plasmodium falciparum / Q000201:enzymology*
D000962:Antimalarials; D000090722:Dihydroorotate Dehydrogenase; D004791:Enzyme Inhibitors; D044925:Oxidoreductases Acting on CH-CH Group Donors