1. Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
2. Department of Chemical Biology, GSK, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, United Kingdom
3. Department of Biochemistry, South Parks Road, Oxford OX1 3QU, United Kingdom
4. MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
5. Department of Chemistry & Biochemistry, University of California Los Angeles, 607 Charles E. Young Drive East, P.O. Box 951569, Los Angeles, California 90095-1569, United States