1. Centre for Molecular Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
2. Computational Chemistry, Oncology, IMED Biotech Unit, AstraZeneca, Cambridge CB10 1XL, U.K.
3. Discovery Biology, Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg 431 50 SE, Sweden