1. Department of New Materials and Biosystems; Max Planck Institute for Intelligent Systems; Heisenbergstr. 3 Stuttgart D-70569 Germany
2. Department of Biophysical Chemistry; University of Heidelberg INF 253; Heidelberg D-69120 Germany
3. Institute for Materials Research; Wetenschapspark 1 Diepenbeek B-3590 Belgium
4. Institute for Advanced Study (IAS) and Center of Integrated Protein Science (CIPSM); Department Chemie; Technische Universität München; Lichtenbergstr. 4 Garching D-85747 Germany