1. Mercachem; Kerkenbos 1013, 6546 BB Nijmegen, P.O. Box 6747 6503 GE Nijmegen The Netherlands
2. Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry; Rheinische Friedrich-Wilhelms-Universität; Dahlmannstr. 2 53113 Bonn Germany