1. Centre for Theoretical and Computational Chemistry, Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
2. CCLRC Daresbury Laboratory, Warrington WA4 4AD, U.K.
3. AstraZeneca, Mereside, Alderley Park, Macclesfield, Cheshire SK10 4TG, U.K.
4. AstraZeneca, Silk Road Business Park, Charter Way, Macclesfield, Cheshire SK10 2NA, U.K.