title: On the mechanism of phosphoenolpyruvate synthetase (PEPs) and its inhibition by sodium fluoride: potential magnesium and aluminum fluoride complexes of phosphoryl transfer.
abstract: Phosphoenolpyruvate synthase (PEPs) catalyzes the conversion of pyruvate to phosphoenolpyruvate (PEP) using a two-step mechanism invoking a phosphorylated-His intermediate. Formation of PEP is an initial step in gluconeogenesis, and PEPs is essential for growth of Escherichia coli on 3-carbon sources such as pyruvate. The production of PEPs has also been linked to bacterial virulence and antibiotic resistance. As such, PEPs is of interest as a target for antibiotic development, and initial investigations of PEPs have indicated inhibition by sodium fluoride. Similar inhibition has been observed in a variety of phospho-transfer enzymes through the formation of metal fluoride complexes within the active site. Herein we quantify the inhibitory capacity of sodium fluoride through a coupled spectrophotometric assay. The observed inhibition provides indirect evidence for the formation of a MgF3(-) complex within the enzyme active site and insight into the phospho-transfer mechanism of PEPs. The effect of AlCl3 on PEPs enzyme activity was also assessed and found to decrease substrate binding and turnover.
authors.affiliation: College of Pharmacy, Dalhousie University, 5968 College St., Halifax, NS B3H 4R2, Canada.
authors.forename: Nicole E
authors.initials: NE
authors.lastname: McCormick
authors.forename: David L
authors.initials: DL
authors.lastname: Jakeman
mesh_terms: D000077410:Aluminum Chloride; D017607:Aluminum Compounds / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D005459:Fluorides / Q000494:pharmacology*; D007700:Kinetics; D017616:Magnesium Compounds / Q000494:pharmacology*; D017866:Phosphotransferases (Paired Acceptors) / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D050743:Pyruvate Synthase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012969:Sodium Fluoride / Q000494:pharmacology*
chemical_list: D017607:Aluminum Compounds; D002712:Chlorides; D004791:Enzyme Inhibitors; D029968:Escherichia coli Proteins; D017616:Magnesium Compounds; D011994:Recombinant Proteins; D000077410:Aluminum Chloride; C031288:magnesium fluoride; D012969:Sodium Fluoride; D050743:Pyruvate Synthase; C506224:ppsA protein, E coli; D017866:Phosphotransferases (Paired Acceptors); C022509:pyruvate, water dikinase; D005459:Fluorides; C032311:aluminum fluoride
keywords: MgF3−/AlF4−; complexes de fluorures métalliques; enzyme inhibition; fluoride; fluorure; inhibition enzymatique; metal fluoride complexes; phosphoenolpyruvate synthase; phosphoénolpyruvate synthase