Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MO: Fachverband Molekülphysik
MO 1: Biomolecules
MO 1.2: Vortrag
Montag, 14. März 2011, 10:45–11:00, TOE 317
A computational study of polyalanine-based peptides and their microsolvation — •Sucismita Chutia, Mariana Rossi, Volker Blum, and Matthias Scheffler — Fritz Haber Institute, Berlin, Germany
Microsolvation is an important method to map the transition of isolated gas-phase peptides to their fully solvated states. In our study, we aim to theoretically identify the lowest energy conformers, the preferred water binding sites, and the influence of water molecules on the structure of two small peptides previously studied in vacuo experiments, Ac-Ala5-LysH+[1] and Ac-Phe-Ala5-LysH+[2]. A basin hopping search with the OPLS-AA force-field in TINKER followed by calculations with the all-electron electronic structure code FHI-aims [3] using the van der Waals corrected [4] PBE density functional is used to determine the low energy conformers. We find both pure and mixed helices among the lowest energy structures of the non-hydrated peptides. During microsolvation, the first water molecule prefers to bind to the protonated lysine end. The subsequent water molecules tend to cluster around the protonated end as well as the carbonyl group. As the number of discrete water molecules increase, a different “more solvated” structure becomes the global minimum. Ab initio molecular dynamics is used to study the stability of some of these structures when fully solvated with explicit solvent molecules. [1] M. Kohtani and M. F. Jarrold, JACS, 126, 8454(2004)[2] J.A. Stearns et al., PCCP, 11,125(2009) [3] V. Blum et al., Comp.Phys.Comm., 180, 2175 (2009)[4] A. Tkatchenko and M. Scheffler, PRL, 102, 073005 (2009)