Mechanism of CB1954 reduction by Escherichia coli nitroreductase

A Christofferson, John Wilkie

Research output: Contribution to journalArticle

18 Citations (Scopus)


NTR (nitroreductase NfsB from Escherichia coli) is a flavoprotein with broad substrate specificity, reducing nitroaromatics and quinones using either NADPH or NADH. One of its substrates is the prodrug CB1954 (5-[aziridin-1-yl]-2,4-dinitrobenzamide), which is converted into a cytotoxic agent; so NTR/CB1954 has potential for use in cancer gene therapy. However, wild-type NTR has poor kinetics and binding with CB1954, and the mechanism for the reduction of CB1954 by NTR is poorly understood. Computational methods have been utilized to study potential underlying reaction mechanisms so as to identify the order of electron and proton transfers that make up the initial reduction step and the sources of the protons. We have used Molecular Dynamics to examine the nature of the active site of the wild-type enzyme and the preferred binding mode of the substrate. A combination of these results has allowed us to unequivocally identify the reaction mechanism for the reduction of CB1954 by NTR.
Original languageEnglish
Pages (from-to)413-418
Number of pages6
JournalBiochemical Society Transactions
Publication statusPublished - 1 Apr 2009


  • hydride transfer
  • electron transfer
  • cancer treatment
  • Escherichia coli nitroreductase
  • 5-[aziridin-1-yl]-2,4-dinitrobenzamide (CB1954)
  • virus-directed enzyme prodrug therapy (VDEPT)


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