1. Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
2. Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, United States
3. Faculty of Biochemistry and Molecular Medicine and Biocenter Oulu, University of Oulu, Aapistie 7B, Oulu 90220, Finland