Conversation 11: No. 2

category image Volume: Conversation 11
Issue Number 2
May 2000
ISBN 0-940030-81-0

DNA-Mediated Electron Transfer: A Sensitive Probe of DNA-Protein Interactions

The ability of the p-stacked array of heterocyclic DNA bases to behave as an efficient conduit for charge migration has been explored using a wide array of experimental approaches. Spectroscopic studies and biochemical assays show that charge transfer through well-stacked DNA can be extremely facile, although sensitive to structural distortions within the DNA base stack. The efficiency of these long-range reactions depends upon the coupling of the electron donor, acceptor and intervening base pairs within the base stack. As a result, base mismatches and stacking disruptions associated with protein binding to the helix can significantly perturb long range charge transfer. DNA-protein interactions which result in the base flipping of a nucleotide out of the DNA p-stack, in particular, dramatically inhibit long-range charge transfer through DNA. Whether these reactions that can occur over large molecular distances, be applied in sensing DNA damage, and be modulated by DNA-binding proteins, are exploited within the cell remains to be determined.

Scott R. Rajski
and Jacqueline K. Barton

The Division of Chemistry and Chemical Engineering
California Institute of Technology
Pasadena, CA 91125


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