1. Department of Environmental Microbiology, Institute of Water and Wetland Research, Radboud University, Nijmegen, The Netherlands
2. Midwest Center for Structural Genomics and Structural Biology Center, Biosciences, Argonne National Laboratory, Lemont, Illinois, USA
3. Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA
4. Soehngen Institute for Anaerobic Microbiology, Nijmegen, The Netherlands