Vabilo na predavanje / Invitation to the Lecture

[Brigita Pirc]

VABILO NA PREDAVANJE /  INVITATION TO THE LECTURE

 

 

 

Prof. dr. Mark Johnson

 

Institut Laue Langevin, Grenoble, France

 

 

Ponedeljek / Monday, 12. 12. 2011, ob / at 13:00


Velika predavalnica Kemijskega inštituta / Lecture Hall at the National Institute of Chemistry; Hajdrihova 19, Ljubljana 


 

Structure and dynamics of hydrogen bonded systems from inelastic scattering: from temperature-driven proton transfer in molecular crystals to denaturation of DNA

 

 

Povzetek / Abstract

 

We have combined neutron scattering and a range of numerical simulations, including phonon calculations and molecular dynamics, to study hydrogen bonds in condensed matter. Two examples from recent and current theses will be presented. The first concerns proton transfer with increasing temperature in short inter-molecular hydrogen bonds. These bonds have unique physical and chemical properties and are thought to play a fundamental role in processes like enzymatic catalysis. By combining elastic and inelastic neutron scattering results with ab initio, lattice dynamics and molecular dynamics simulations, low frequency lattice modes are identified which modulate the potential energy surface of the hydrogen bond proton and drive proton transfer. New experimental data confirm and give further insight into the mechanism of proton transfer.

 

The second example concerns phonons of DNA. In particular acoustic phonons give direct access to the elastic properties of DNA which are important for its interaction with proteins and more generally its function. Inelastic X-ray and neutron scattering measure different modes relating to the interaction between base-pairs and the way this is modulated by the helix structure. The experimental data is interpreted with the aid of large scale, all-atom, phonon calculations. The combination of simulations and inelastic scattering data give insight into the stiffness of DNA and its structural integrity on different length scales.

 

Vljudno vabljeni! / Kindly invited!

 

 

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