1. Laboratory for Molecular Microbiology, Department of Biology; Philipps-University Marburg; Karl-von-Frisch Str. 8 Marburg D-35043 Germany
2. LOEWE-Center for Synthetic Microbiology; Philipps-University Marburg; Hans-Meerweinstr. 6 Marburg D-35043 Germany
3. Institute of Biochemistry, Heinrich-Heine-University Düsseldorf; Universitätsstr. 1 Düsseldorf D-40225 Germany