Electrochemistry of the [4Fe4S] Cluster in Base Excision Repair Proteins: Tuning the Redox Potential with DNA

Phillip L. Bartels, Andy Zhou, Anna R. Arnold, Nicole N. Nuñez, Frank N. Crespilho, Sheila S. David, Jacqueline K. Barton

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

Escherichia coli endonuclease III (EndoIII) and MutY are DNA glycosylases that contain [4Fe4S] clusters and that serve to maintain the integrity of the genome after oxidative stress. Electrochemical studies on highly oriented pyrolytic graphite (HOPG) revealed that DNA binding by EndoIII leads to a large negative shift in the midpoint potential of the cluster, consistent with stabilization of the oxidized [4Fe4S]3+ form. However, the smooth, hydrophobic HOPG surface is nonideal for working with proteins in the absence of DNA. In this work, we use thin film voltammetry on a pyrolytic graphite edge electrode to overcome these limitations. Improved adsorption leads to substantial signals for both EndoIII and MutY in the absence of DNA, and a large negative potential shift is retained with DNA present. In contrast, the EndoIII mutants E200K, Y205H, and K208E, which provide electrostatic perturbations in the vicinity of the cluster, all show DNA-free potentials within error of wild type; similarly, the presence of negatively charged poly-l-glutamate does not lead to a significant potential shift. Overall, binding to the DNA polyanion is the dominant effect in tuning the redox potential of the [4Fe4S] cluster, helping to explain why all DNA-binding proteins with [4Fe4S] clusters studied to date have similar DNA-bound potentials.

Original languageEnglish (US)
Pages (from-to)2523-2530
Number of pages8
JournalLangmuir
Volume33
Issue number10
DOIs
StatePublished - Mar 14 2017

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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    Bartels, P. L., Zhou, A., Arnold, A. R., Nuñez, N. N., Crespilho, F. N., David, S. S., & Barton, J. K. (2017). Electrochemistry of the [4Fe4S] Cluster in Base Excision Repair Proteins: Tuning the Redox Potential with DNA. Langmuir, 33(10), 2523-2530. https://doi.org/10.1021/acs.langmuir.6b04581