1. Albrecht-von-Haller-Institute for Plant Sciences and Göttingen Center for Molecular Biosciences, Georg-August-University Göttingen, Ernst-Caspari-Haus, Justus-von-Liebig-Weg 11, D-37077 Göttingen, Germany
2. Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Strasse 3, D-06120 Halle/Saale, Germany
3. Institute of Organic Chemistry, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Strasse 3, D-06120 Halle/Saale, Germany
4. Department of Chemistry, Rutgers University, Newark, New Jersey 07102