1. Cell and Molecular Biology Program, Institute of Biotechnology; University of Helsinki; P.O. Box 56 FI-00014 Helsinki Finland
2. Minerva Foundation Institute for Medical Research; Tukholmankatu 8 FI-00290 Helsinki Finland
3. VTT Technical Research Centre of Finland; Tietotie 2 FIN 02044 VTT Espoo Finland
4. Computer-Aided Drug Design; Orion Pharma; P.O. Box 65 02101 Espoo Finland