1. Institute of Experimental Haematology and Transfusion Medicine, University Clinic Bonn, Bonn, Germany.
2. Institute of Human Genetics, Biocenter—University of Würzburg, Würzburg, Germany.
3. Institute of Transfusion Medicine and Immunohaematology, DRK Blood Donor Service Baden-Württemberg-Hessen, Frankfurt/Main, Germany.
4. Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt/Main, Germany.