Physics of DNA: experimental observations which raise modelling questions

Michel Peyrard (Physics of Biological Systems, Ecole Normale Supérieure de Lyon, France)

Abstract: To play its role in the cell, DNA is a highly dynamical molecule. The base pairs, which encode the genetic information, fluctuate widely. Physical experiments can be used to probe these fluctuations. We have used neutron scattering to measure the size of the regions that stay well ordered, on the scale of a few tens of base pairs. Magnetic birefringence measurements have provided a view of the rigidity of DNA at a broader scale. But the experimental data alone are not very helpful if they are not supplemented by a theoretical analysis for their understanding. The talk will present the experimental facts and discuss their analysis [1-3]. The results suggest that fluctuational openings of DNA could play a larger role than was previously thought.

[1] Andrew Wildes, Nikos Theodorakopoulos, Jessica Valle-Orero, Santiago Cuesta-Lopez, Jean-Luc Garden, and Michel Peyrard, The thermal denaturation of DNA studied with neutron scattering, PRL 106 048101-1-4 (2011)
[2]Andrew Wildes, Nikos Theodorakopoulos, Jessica Valle-Orero, Santiago Cuesta-Lopez, Jean-Luc Garden, and Michel Peyrard, Structural correlations and melting of B-DNA fibers, Phys. Rev. E 83 061923-1-11 (2011)
[3] N. Theodorakopoulos and M. Peyrard, Base Pair Openings and Temperature Dependence of DNA Flexibility, PRL 108 078104-1-4 (2012)