1. Department
of Molecular Immunology, Beckman Research Institute of the City of Hope, 1500 E. Duarte Road, Duarte, California 91010, United States
2. Heptares Therapeutics Ltd, BioPark, Broadwater Road, Welwyn Garden City AL7 3AX, U.K.
3. Membrane Protein Structure Function Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Department of Health and Human Services, Rockville, Maryland 20852, United States
4. MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, U.K.