DNA bending by asymmetrically tethered cations: Influence of tether flexibility

Philip R. Hardwidge, Dong Kye Lee, Thazha P. Prakash, Beatriz Iglesias, Robert B. Den, Christopher Switzer, L. James Maher

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Background: We have been studying the proposal that laterally asymmetric charge neutralization along the DNA double helix can induce collapse toward the neutralized surface. Results of previous experiments implied that such a phenomenon can occur, suggesting a role for local interphosphate repulsive forces in DNA shape and rigidity. Results: We now show that, whereas six ammonium ions tethered to one DNA face on flexible propyl chains can induce detectable DNA curvature, tethering of ammonium ions on rigid propynyl tethers does not induce DNA curvature. Molecular modeling indicates differing propensities for phosphate salt bridge formation between propyl- and propynyl-tethered ammonium ions. Conclusions: Ammonium ion localization is suggested as a key factor in induced bending. Rigidification of the double helix by stacking of propyne groups cannot be excluded.

Original languageEnglish (US)
Pages (from-to)967-980
Number of pages14
JournalChemistry and Biology
Issue number10
StatePublished - 2001


  • Asymmetric neutralization
  • Base analogs
  • Cations
  • DNA bending
  • DNA curvature
  • Electrophoresis
  • Phosphate

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Pharmacology
  • Drug Discovery
  • Clinical Biochemistry


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