1. Institute of Biophysics and Institute of Organic Chemistry, University of Linz, Altenberger Strasse 69, A-4040 Linz, Austria, Center for Biomedical Nanotechnology, Upper Austrian Research GmbH, A-4020 Linz, Austria, and Institute of Biochemistry, Biocenter, Johann Wolfgang Goethe-University, Max-von-Laue-Strasse 9, D-60438 Frankfurt, Germany