Probing ligand-binding pockets of the mevalonate pathway enzymes from Streptococcus pneumoniae

Scott T. Lefurgy, Sofia B. Rodriguez, Chan Sun Park, Sean Cahill, Richard B. Silverman, Thomas S. Leyh

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Diphosphomevalonate (Mev·pp) is the founding member of a new class of potential antibiotics targeting the Streptococcus pneumoniae mevalonate (Mev) pathway. We have synthesized a series of Mev·pp analogues designed to simultaneously block two steps in this pathway, through allosteric inhibition of mevalonate kinase (MK) and, for five of the analogues, by mechanismbased inactivation of diphosphomevalonate decarboxylase (DPM-DC). The analogue series expands the C3-methyl group of Mev·pp with hydrocarbons of varying size, shape, and chemical and physical properties. Previously, we established the feasibility of a prodrug strategy in which unphosphorylated Mev analogues could be enzymatically converted to the active Mev·pp forms by the endogenous MK and phosphomevalonate kinase.Wenowreport the kinetic parameters for the turnover of non-, mono-, and diphosphorylated analogues as substrates and inhibitors of the three mevalonate pathway enzymes. The inhibition of MK by Mev·pp analogues revealed that the allosteric site is selective for compact, electron-rich C3-subsitutents. The lack of reactivity of analogues with DPM-DC provided evidence, counter to the existing model, for a decarboxylation transition state that is concerted rather than dissociative. The Mev pathway is composed of three structurally and functionally conserved enzymes that catalyze consecutive steps in a metabolic pathway. The current work reveals that these enzymes exhibit significant differences in specificity toward R-group substitution at C3 and that these patterns are explained well by changes in the volume of the C3 R-group-binding pockets of the enzymes.

Original languageEnglish (US)
Pages (from-to)20654-20663
Number of pages10
JournalJournal of Biological Chemistry
Volume285
Issue number27
DOIs
StatePublished - Jul 2 2010

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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