1. Organic and Bioorganic Chemistry, Department of Chemistry; Bielefeld University; PO Box 100131 33501 Bielefeld Germany
2. Department of Bioorganic Chemistry; Wrocław University of Science and Technology; Wybrzeze Wyspianskiego 27 50-370 Wrocław Poland
3. Center for Integrated Protein Science, Department of Biosciences; TU Munich; Emil-Erlenmeyer-Forum 8 85354 Freising Germany
4. Inorganic and Structural Chemistry, Department of Chemistry; Bielefeld University; PO Box 100131 33501 Bielefeld Germany