Berlin 2014 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 11: Biomolecules 1
MO 11.3: Vortrag
Mittwoch, 19. März 2014, 14:30–14:45, BEBEL HS213
Histidine-cation interaction and microsolvation from first principles — •Markus Schneider1, Volker Blum1,2, Carsten Baldauf1, and Matthias Scheffler1 — 1Fritz-Haber-Institut der MPG, Berlin, Germany — 2MEMS, Duke University, Durham, U.S.A.
Protein-cation interactions play a crucial role in shaping the three-dimensional structure of protein. Of special importance here is the histidine side chain that is, among other examples, involved in the metal cation complexation by the Alzheimer Aβ peptide. Our work aims for understanding the binding of cations by histidine as well as its effect on the peptide structure from first principles. However, the first critical point is the appropriateness of the chosen level of theory for quantitative predictions of such interactions. To that end, we focus on the effect of microsolvation, with either Zn2+ or a H2O molecule or both in competition, on the protonation state of the His sidechain. We first assemble a large ensemble of possible conformations from empirical force field calculations. Then, we use these conformations to benchmark the performance of density-functional theory based methods against high-level coupled-cluster calculations. In particular, we assess the PBE generalized gradient approximation as well as the PBEh and B3LYP hybrid density functionals, all of them corrected for long-range dispersion with either the pairwise Tkatchenko-Scheffler scheme or a newly developed many-body dispersion scheme (MBD*).