1. Molecular Dynamics and Biomolecular Simulation Group, Department of Theoretical Chemistry and Molecular Structural Biology, University of Vienna, Währingerstrasse 17, 1090 Vienna, Austria
2. Laboratoire de Chimie Biophysique, ISIS, Université Louis Pasteur, 67000 Strasbourg, France, and Department of Chemical Biology, 12 Oxford Street, Harvard University, Cambridge, Massachusetts 02138