Modeling and Analysis of Intercalant Effects on Circular DNA Conformation

Eric Krueger, Jiwook Shim, Arman Fathizadeh, Angela Nicole Chang, Basheer Subei, Katie M. Yocham, Paul H. Davis, Elton Graugnard, Fatemeh Khalili-Araghi, Rashid Bashir, David Estrada, Daniel Fologea

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


The large-scale conformation of DNA molecules plays a critical role in many basic elements of cellular functionality and viability. By targeting the structural properties of DNA, many cancer drugs, such as anthracyclines, effectively inhibit tumor growth but can also produce dangerous side effects. To enhance the development of innovative medications, rapid screening of structural changes to DNA can provide important insight into their mechanism of interaction. In this study, we report changes to circular DNA conformation from intercalation with ethidium bromide using all-atom molecular dynamics simulations and characterized experimentally by translocation through a silicon nitride solid-state nanopore. Our measurements reveal three distinct current blockade levels and a 6-fold increase in translocation times for ethidium bromide-treated circular DNA as compared to untreated circular DNA. We attribute these increases to changes in the supercoiled configuration hypothesized to be branched or looped structures formed in the circular DNA molecule. Further evidence of the conformational changes is demonstrated by qualitative atomic force microscopy analysis. These results expand the current methodology for predicting and characterizing DNA tertiary structure and advance nanopore technology as a platform for deciphering structural changes of other important biomolecules.

Original languageEnglish (US)
Pages (from-to)8910-8917
Number of pages8
JournalACS Nano
Issue number9
StatePublished - Sep 27 2016

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)


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