Free-Energy Profiles for A-/B-DNA Conformational Transitions in Isolated and Aggregated States from All-Atom Molecular Dynamics Simulation

Cheng Tsung Lai, George C Schatz

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1 Citation (Scopus)

Abstract

In ordinary aqueous solution, B-DNA is the major structural form of DNA. After the addition of ethanol, DNA is thought to be aggregated/condensed in the A-form structure. However, there is uncertainty as to whether the B-To-A conformational change is connected to the aggregation/condensation steps. In this study, we performed all-Atom molecular dynamics simulations and calculated the free-energy surface involved in the A/B conformational transition for isolated and aggregated Dickerson-Drew dodecamers (DDDs) in water and 85% ethanol environments. We found in the case of an isolated DDD, the overall free-energy profile is entirely downhill to give the B-DNA conformation in both water and 85% ethanol. However, in the aggregated state and 85% ethanol environment, there is a free-energy minimum associated with the A-DNA region in addition to the global B-DNA minimum, and there is a â3 kcal/mol free-energy barrier to the A-To-B conformational change. The molecular dynamics results suggest that aggregation of DNA is essential for forming A-DNA.

Original languageEnglish
Pages (from-to)7990-7996
Number of pages7
JournalJournal of Physical Chemistry B
Volume122
Issue number33
DOIs
Publication statusPublished - Aug 23 2018

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ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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