Fast photoinduced electron transfer through DNA intercalation

Catherine J. Murphy, Michelle R. Arkin, Naresh D. Ghatlia, Stefan Bossmann, Nicholas J. Turro, Jacqueline K. Barton

Research output: Contribution to journalArticlepeer-review


We report evidence for fast photoinduced electron transfer mediated by the DNA helix that requires metal complexes that are avid intercalators of DNA. Here the donor bis(phenanthroline)(dipyridophenazine)ruthenium(II) [Ru(phen)2dppz2+] and acceptor bis(9,10-phenanthrenequinone diimine)(phenanthroline)rhodium(III) [Rh(phi)2phen3+] intercalate into DNA with K(b) > 106 M-1. Luminescence quenching experiments in the presence of two different lengths of DNA yield upward-curving Stern-Volmer plots and the loss of luminescence intensity far exceeds the change in emission lifetimes. In the presence of a nonintercalative electron acceptor, Ru(NH3)6/3+, Ru(phen)2dppz2+ luminescence is quenched much less efficiently compared to that found for the intercalative Rh(phi)2phen3+ quencher and follows linear Stern-Volmer kinetics; steady-state and time-resolved Stern-Volmer plots are comparable in scale. These experiments are consistent with a model involving fast long-range electron transfer between intercalators through the DNA helix.

Original languageEnglish (US)
Pages (from-to)5315-5319
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number12
StatePublished - Jun 7 1994
Externally publishedYes


  • DNA mediation
  • long-range electron transfer
  • luminescence quenching
  • metallointercalators
  • spectroscopic probes

ASJC Scopus subject areas

  • Genetics
  • General


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