1. Centre for Computational Science, Department of Chemistry, University College London, London WC1H 0AJ, U.K.
2. GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K.
3. GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426, United States
4. Advanced Research Computing Centre, University College London, London WC1H 0AJ U.K.
5. Institute for Informatics, Faculty of Science, University of Amsterdam, 1098XH Amsterdam, The Netherlands