Electronic coupling of the stacked heterocyclic base pairs in DNA duplexes makes DNA a promising biomaterial for conducting charges. The process, DNA-mediated charge transport (CT), has recently shown pivotal biological functions in repairing/damaging DNA and signalling proteins via one-electron oxidation over long genomic distance.[1] Utilizing various photooxidation systems, the efficiency of DNA to transport charge had been well established.[2] However, details of how CT is affected by external interference had not been fully characterized. Considering that magnetic field (MF) can affect electronic properties of nucleic acids and alter chemical reactions that involve radical intermediates, herein we have investigated the effects of external MF on DNA mediated CT.DNA Assemblies containing guanine kinetic traps (8CPG) placed at different distances away from covalently tethered photooxidant anthraquinone (AQ), were constructed to measure CT efficiencies in the presence of MF.  After applying external MF, damages to both the proximal and distal 8CPG via photo-initialized DNA CT are increased by 7- and 4- folds, respectively. The acceleration of CT is closely related to the strength of the applied MF, where damage to 8CPG increased linearly with MF up to 45 mT. Two factors may account for MF induced acceleration of DNA CT. Direct photoxidation between AQ and 8CPG shows that external MF can enhance the charge injections to DNA via stabilizing reduced photooxidant radical, 3AQ*-. Secondly, more efficient CT through duplex DNA containing mismatch than well-matched DNA is achieved by applying external MF, which implies that external MF can manipulate the alignments of base pair stacking to promote high accessibility of DNA bridge to the CT-active conformation. Herein our results suggest that external magnetic fields could be a promising approach to enhance the electronic conductivity of duplex DNA and may open a new avenue for designing biomolecular wire based nanodevices.Reference:1. EJ Merino, AK Boal, JK Barton, Curr Opi Chem Biol. 2008 , 12, 229.2. FW Shao, MA O'Neill, JK Barton, Proc. Natl. Acad. Sci. USA, 2004,  101, 17914.

Acceleration of DNA mediated charge transport by external magnetic fields

248th National Meeting (2014)

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