1. York Structural Biology Laboratory and York Biomedical Research Institute, Department of Chemistry, University of York, York YO10 5DD, U.K.
2. Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K.
3. GSK, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K.
4. GSK Global Health, Tres Cantos, 28760 Madrid, Spain
5. York Biomedical Research Institute, Department of Biology, University of York, York YO10 5NG, U.K.