Transport and reactions of radical cations in DNA: Steric and energetic control of reactivity

Ibrahim M. Abdou, Edna K. Boone, Huachuan Cao, Cheryl Crummie, Gary B. Schuster

Research output: Contribution to journalArticlepeer-review


A series of DNA oligomers was prepared that contain an anthraquinone group (AQ) linked to a 5'-terminus and have 8-methylguanine (MG) or 8-bromoguainine (BG) substituted for G at various positions. Irradiation of the AQ injects a radical cation into the oligonucleotide, which migrates through the DNA and reacts primarily at Gn sites where n = 2 or 3. Substitution with MG which has an oxidation potential (E OX) slightly below G, traps the migrating radical cation, substitution with BG, which has an EOX above G, does not. However, both MG and BG affect the relative reactivity of the guanines in Gn steps. Moreover, a (G)3 sequence has a much smaller effect on the efficiency of radical cation migration than does MG, which demonstrates that the EOX of G in the (G) 3 sequence is above that of MG. These findings show that the EOX of the base controls the efficiency of radical cation transport and that steric effects influence the relative reactivity of G in Gn sequences.

Original languageEnglish
Pages (from-to)419-427
Number of pages9
JournalResearch on Chemical Intermediates
Issue number4-5
Publication statusPublished - 2004


  • Duplex irradiation
  • Energetic control
  • Radical cations
  • Steric control

ASJC Scopus subject areas

  • General Chemistry


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