title: Design, synthesis, and evaluation of inhibitors of pyruvate phosphate dikinase.
abstract: Pyruvate phosphate dikinase (PPDK) catalyzes the phosphorylation reaction of pyruvate that forms phosphoenolpyruvate (PEP) via two partial reactions: PPDK + ATP + P(i) → PPDK-P + AMP + PP(i) and PPDK-P + pyruvate → PEP + PPDK. Based on its role in the metabolism of microbial human pathogens, PPDK is a potential drug target. A screen of substances that bind to the PPDK ATP-grasp domain active site revealed that flavone analogues are potent inhibitors of the Clostridium symbiosum PPDK. In silico modeling studies suggested that placement of a 3–6 carbon-tethered ammonium substituent at the 3′- or 4′-positions of 5,7-dihydroxyflavones would result in favorable electrostatic interactions with the PPDK Mg-ATP binding site. As a result, polymethylene-tethered amine derivatives of 5,7-dihydroxyflavones were prepared. Steady-state kinetic analysis of these substances demonstrates that the 4′-aminohexyl-5,7-dyhydroxyflavone 10 is a potent competitive PPDK inhibitor (K(i) = 1.6 ± 0.1 μM). Single turnover experiments were conducted using 4′-aminopropyl-5,7-dihydroxyflavone 7 to show that this flavone specifically targets the ATP binding site and inhibits catalysis of only the PPDK + ATP + P(i) → PPDK-P + AMP PP(i) partial reaction. Finally, the 4′-aminopbutyl-5,7-dihydroxyflavone 8 displays selectivity for inhibition of PPDK versus other enzymes that utilize ATP and NAD.
authors.affiliation: Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States.
authors.forename: Chun
authors.initials: C
authors.lastname: Wu
authors.forename: Debra
authors.initials: D
authors.lastname: Dunaway-Mariano
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Mariano
mesh_terms: D001665:Binding Sites; D002384:Catalysis; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry; D047309:Flavones / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010766:Phosphorylation; D011772:Pyruvate, Orthophosphate Dikinase / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism
chemical_list: C582142:4'-aminopbutyl-5,7-dihydroxyflavone; C582141:4'-aminopropyl-5,7-dihydroxyflavone; D004791:Enzyme Inhibitors; D047309:Flavones; D011772:Pyruvate, Orthophosphate Dikinase