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Updated: Aug 17, 2026

CD Spectroscopy to Study DNA-Protein Interactions
Published on: February 10, 2022
UV spectra and excitation delocalization in DNA: influence of the spectral width
Emanuela Emanuele1, Dimitra Markovitsi, Philippe Millié
1Laboratoire Francis Perrin, CEA/DSM/DRECAM/SPAM-CNRS URA, 2453 CEA Saclay, 91191 Gif-sur-Yvette, France.
Abstract:
The singlet excited states of the model DNA duplex (dA)10.(dT)10 are studied. Calculations are performed in the exciton theory framework. Molecular dynamics calculations provide the duplex geometry. The dipolar coupling is determined using atomic transition charges. The monomer transition energies are simulated by Gaussian functions resembling the absorption bands of nucleosides in aqueous solutions. Most of the excited states are found to be delocalized over at least two bases and result from the mixing of different monomer states. Their properties are only weakly affected by conformational changes of the double helix. On average, the highest oscillator strength is carried by the upper eigenstates. The duplex absorption spectra are shifted a few nanometers to higher energies with respect to the spectra of noninteracting monomers. The states with larger spatial extent are located close to the maximum of the absorption spectrum.
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