1. Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Str. 3a, D-06120 Halle/Saale, Germany
2. Institute of Biochemistry, Martin Luther University Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Str. 3a, D-06120 Halle (Saale), Germany
3. Department of Chemistry, University Cologne, Greinstr. 4, D-50939 Köln, Germany