1. Ludwig-Maximilians-Universität München; Department Chemie; Butenandtstr. 5-13 81377 München Germany
2. Department of Microbiology, Institute of Wetland and Water Research; Radboud University; Heyendaalseweg 135 6525 AJ Nijmegen The Netherlands
3. Department of Biomolecular Mechanisms; Max-Planck Institute for Medical Research; Jahnstrasse 29 69120 Heidelberg Germany