1. Department of Life Sciences, Imperial College London, Exhibition Road, London, South Kensington, SW7 2AZ, U.K.
2. Membrane Protein Lab, Diamond Light Source, Harwell Science and Innovation Campus, Chilton, Oxfordshire, OX11 0DE, U.K.
3. Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot, Oxfordshire OX11 0FA, U.K.