willem.vanberkel@wur.nl 3 Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, USA; gassner@sfsu.edu 4 Allgemeine Biochemie, Technische Universität Dresden, 01062 Dresden, Germany; karl-heinz.van_pee@tu-dresden.de 5 Microbial ...