1. Molecular Structure and Function, Imperial Cancer Research Fund; 44 Lincoln's Inn Fields London WC2A 3PX GB
2. Present address: Laboratoire d'Enzymologie et de Biochimie Structurales, UPR9063 CNRS-Université Paris-Sud, Bât. 34; 1 Avenue de la Terrasse 91198 Gif-sur-Yvette France
3. Biomolecular Modelling, Imperial Cancer Research Fund; 44 Lincoln's Inn Fields London WC2A 3PX GB
4. Protein Isolation and Cloning Laboratories, Imperial Cancer Research Fund; 44 Lincoln's Inn Fields London WC2A 3PX GB
5. Present address: Institut für Physikalische Chemie, Universität Graz, Heinrichstraße 28; 8010 Graz Austria
6. ICRF Clare Hall Laboratories; South Mimms Herts EN6 3LD GB