AUTEUR: Dr J. P. Lewis
<br> Assistant Research Professor
<br> Department of Physics and Astronomy
<br> Brigham Young University
<br> N233 ESC P.O. Box 24658
<br> Provo, UTAH 84602-4658
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<br>TITRE : Investigation of DNA dynamics and effects on electronic structure
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<br>DATE      Lundi 31 Mars 2003 à 11h
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<br>LIEU       Université P. & M. Curie
<br>        4, place Jussieu - 75005 Paris
<br>        Laboratoire de Chimie Théorique
<br>        Tour 22 - 1er étage - Couloir 22-23
<br>        Salle de Conférence
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SUMMARY: 
The first atomistic density functional theory-based investigation of a
large DNA strand (10 base pairs) was reported by J.P. Lewis et al. (1997).
Since that work, considerable improvements to our ab initio local-orbital
method (called FIREBALL) have been introduced. We will discuss some of these
improvements in reference to our efforts to calculate large biomolecular
systems, in particular DNA. In the literature, much theoretical work has been
done in the area of trying to understand the electronic structure and electron
(hole)-transfer properties of DNA. But, due to the size of the problem,
atomistic models with a quantum mechanical picture for large DNA strands
containing several base pairs have made very little contribution in this area.


One important avenue of investigation is the understanding of how the dynamics
of the DNA strand might affect the electronic structure and hence the electron
(hole)-transport. We will discuss results where state-of-the-art molecular
dynamics simulations, including an explicit representation of solvent and
counterions and a proper treatment of the long-ranged electrostatic
interactions, of duplex DNA were performed. Snapshots of the trajectory were
coupled to calculations of the electronic structure. Preliminary results for
a 'time-dependent' electronic structure of DNA will then be reported.