Inhibition of IspH, a [4Fe-4S]2+ enzyme involved in the biosynthesis of isoprenoids via the methylerythritol phosphate pathway

J Am Chem Soc. 2013 Feb 6;135(5):1816-22. doi: 10.1021/ja309557s. Epub 2013 Jan 29.


The MEP pathway, which is absent in animals but present in most pathogenic bacteria, in the parasite responsible for malaria and in plant plastids, is a target for the development of antimicrobial drugs. IspH, an oxygen-sensitive [4Fe-4S] enzyme, catalyzes the last step of this pathway and converts (E)-4-hydroxy-3-methylbut-2-en-1-yl diphosphate (HMBPP) into the two isoprenoid precursors: isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). A crucial step in the mechanism of this enzyme is the binding of the C4 hydroxyl of HMBPP to the unique fourth iron site in the [4Fe-4S](2+) moiety. Here, we report the synthesis and the kinetic investigations of two new extremely potent inhibitors of E. coli IspH where the OH group of HMBPP is replaced by an amino and a thiol group. (E)-4-Mercapto-3-methylbut-2-en-1-yl diphosphate is a reversible tight-binding inhibitor of IspH with K(i) = 20 ± 2 nM. A detailed kinetic analysis revealed that (E)-4-amino-3-methylbut-2-en-1-yl diphosphate is a reversible slow-binding inhibitor of IspH with K(i) = 54 ± 19 nM. The slow binding behavior of this inhibitor is best described by a one-step mechanism with the slow step consisting of the formation of the enzyme-inhibitor (EI) complex.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biocatalysis
  • Biosynthetic Pathways / drug effects
  • Dose-Response Relationship, Drug
  • Enzyme Inhibitors / chemical synthesis
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • Erythritol / analogs & derivatives
  • Erythritol / chemistry
  • Erythritol / pharmacology*
  • Escherichia coli Proteins / antagonists & inhibitors*
  • Escherichia coli Proteins / isolation & purification
  • Escherichia coli Proteins / metabolism*
  • Kinetics
  • Models, Molecular
  • Molecular Structure
  • Oxidoreductases / antagonists & inhibitors*
  • Oxidoreductases / isolation & purification
  • Oxidoreductases / metabolism*
  • Structure-Activity Relationship
  • Sugar Phosphates / chemical synthesis
  • Sugar Phosphates / chemistry
  • Sugar Phosphates / pharmacology*
  • Terpenes / chemistry
  • Terpenes / metabolism*


  • Enzyme Inhibitors
  • Escherichia coli Proteins
  • Sugar Phosphates
  • Terpenes
  • Oxidoreductases
  • ispH protein, E coli
  • Erythritol