1. Institute of Biochemistry and Molecular Physiology, Potsdam University, c/o Biotechnologiepark Luckenwalde, Im Biotechnologiepark, 14943 Luckenwalde, Germany, ZEIK, Potsdam University, Am Neuen Palais 10, 14469 Potsdam, Germany, and Department of Chemistry, The University of Kansas, Lawrence, Kansas 66045