1. Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy University of Helsinki P.O. Box 56 (Viikinkaari 5 E) 00014 Helsinki Finland
2. Department of Biosciences, Division of Biochemistry University of Helsinki P.O. Box 56 (Viikinkaari 9) 00014 Helsinki Finland
3. Malaria Research Laboratory, Translational Immunology Research Program, Department of Bacteriology and Immunology, Haartman Institute University of Helsinki P.O. Box 21 (Haartmaninkatu 3) 00014 Helsinki Finland
4. School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology University of Leeds, Clarendon Way Leeds LS2 9JT UK