title: Inhibition of bacterial mevalonate diphosphate decarboxylase by eriochrome compounds.
abstract: Mevalonate diphosphate decarboxylase (MDD; EC 4.1.1.33) catalyzes the irreversible decarboxylation of mevalonate diphosphate in the mevalonate pathway to form isopentenyl diphosphate, which is a precursor in the biosynthesis of many essential polyisoprenoid natural products, including sterols. In low G/C Gram-positive bacteria, which utilize the mevalonate pathway, MDD is required for cell viability and thus is a potential target for development of antibiotic drugs. To identify potential inhibitors of the enzyme, the National Cancer Institute's Mechanistic Diversity Set library of compounds was screened for inhibitors of Staphylococcus epidermidis MDD. From this screen, the compound Eriochrome Black A (EBA), an azo dye, was found to inhibit the enzyme with an IC50 value<5μM. Molecular docking of EBA into a crystal structure of S. epidermidis MDD suggested binding at the active site. EBA, along with the related Eriochrome B and T compounds, was evaluated for its ability to not only inhibit enzymatic activity but to inhibit bacterial growth as well. These compounds exhibited competitive inhibition towards the substrate mevalonate diphosphate, with Ki values ranging from 0.6 to 2.7μM. Non-competitive inhibition was observed versus ATP indicating binding of the inhibitor in the mevalonate diphosphate binding site, consistent with molecular docking predictions. Fluorescence quenching analyses also supported active site binding of EBA. These eriochrome compounds are effective at inhibiting S. epidermidis cell growth on both solid media and in liquid culture (MIC50 from 31 to 350μM) raising the possibility that they could be developed into antibiotic leads targeting pathogenic low-G/C Gram-positive cocci.
authors.affiliation: Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, United States.
authors.forename: D Andrew
authors.initials: DA
authors.lastname: Skaff
authors.affiliation: Division of Cell Biology and Biophysics, University of Missouri-Kansas City, Kansas City, MO 64110, United States.
authors.forename: William J
authors.initials: WJ
authors.lastname: McWhorter
authors.affiliation: Division of Cell Biology and Biophysics, University of Missouri-Kansas City, Kansas City, MO 64110, United States.
authors.forename: Brian V
authors.initials: BV
authors.lastname: Geisbrecht
authors.affiliation: Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, United States.
authors.forename: Gerald J
authors.initials: GJ
authors.lastname: Wyckoff
authors.affiliation: Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, United States. Electronic address: miziorkoh@umkc.edu.
authors.forename: Henry M
authors.initials: HM
authors.lastname: Miziorko
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D001391:Azo Compounds / Q000737:chemistry*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics; D002262:Carboxy-Lyases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics; D004791:Enzyme Inhibitors / Q000737:chemistry*; D057166:High-Throughput Screening Assays; D007700:Kinetics; D008798:Mevalonic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D062105:Molecular Docking Simulation; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D054852:Small Molecule Libraries; D013212:Staphylococcus epidermidis / Q000737:chemistry* / Q000201:enzymology
chemical_list: D001391:Azo Compounds; D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D011994:Recombinant Proteins; D054852:Small Molecule Libraries; C007618:Eriochrome Blue SE; C039986:eriochrome black A; C046285:5-diphosphomevalonic acid; D000255:Adenosine Triphosphate; D002262:Carboxy-Lyases; C022503:pyrophosphomevalonate decarboxylase; C014527:Eriochrome Black T; D008798:Mevalonic Acid
keywords: Enzyme inhibitors; Isoprenoid biosynthesis; Mevalonate diphosphate decarboxylase; Mevalonate pathway