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- Title
Transitions between secondary structures in isolated polyalanines.
- Authors
Calvo, F.; Poulain, P.
- Abstract
Monte Carlo simulations of gas-phase polyalanine peptides have been carried out with the Amber ff96 force field. A low-temperature structural transition takes place between the α-helix stable conformation and β-sheet structures, followed by the unfolding phase change. The transition state ensembles connecting the helix and sheet conformations are investigated by sampling the energy landscape along specific geometric order parameters as putative reaction coordinates, namely the electric dipole μ, the end-to-end distance d, and the gyration radius Rg. By performing series of shooting trajectories, the committor probabilities and their distributions are obtained, revealing that only the electric dipole provides a satisfactory transition coordinate for the α↔β interconversion. The nucleus at the transition is found to have a high helical content.
- Subjects
PHASE transitions; PEPTIDES; ALANINE; MONTE Carlo method; ORDER-disorder models; DIPOLE moments; LOW temperatures
- Publication
European Physical Journal D (EPJ D), 2009, Vol 51, Issue 1, p15
- ISSN
1434-6060
- Publication type
Article
- DOI
10.1140/epjd/e2008-00096-0