Berlin 2005 – wissenschaftliches Programm

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AKB: Biologische Physik

AKB 90: Protein Folding and Molecular Dynamics

AKB 90.1: Vortrag

Mittwoch, 9. März 2005, 14:00–14:15, TU H2013

Helical Alanine Polypeptides: DFT versus Force-Field Results — •Marcus John, Joel Ireta und Matthias Scheffler — Fritz-Haber-Institut der Max-Planck-Gesellschaft

Recently it became possible to calculate different conformations of the secondary structure of proteins fully including the hydrogen bond (hb) cooperativity by means of density functional theory (DFT). Although the computational effort restricts this approach to the treatment of only a few conformations it nevertheless provides important insight into the stabilizing function of hbs. DFT in the PBE approximation to the exchange-correlation functional revealed the existence of three different minima on the potential-energy surface of a helix, corresponding to the π-, α-, and 3₁₀ conformations [1]. A comparison with some existing force fields (CHARMM27 or AMOEBA) shows that they are not able to reproduce these different basins. We conjecture that this is due to the inability of current force fields to model the effect of cooperative hbs properly. In this contribution we provide an analysis of this phenomenon which may help to develop improved force fields.

[1] J. Ireta, M. Scheffler, J. Neugebauer, A. Rojo, M. Galvan submitted to PRL