1. Biomedical Sciences Research Complex, North Haugh, University of St. Andrews, Fife KY16 9ST, UK.
2. Division of Structural Biology, Wellcome Trust Centre of Human Genomics, Roosevelt Drive, Oxford OX3 7BN, UK.
3. Institute of Microbiology, Department of Biology, Eidgenössische Technische Hochschule (ETH) Zürich, Zürich, Switzerland.
4. Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule (ETH) Zürich, Zürich, Switzerland.
5. Department of Biochemistry, Molecular Biology, and Biophysics, and BioTechnology Institute, University of Minnesota–Twin Cities, St. Paul, MN 55108, USA.
6. State Key Laboratory of Biotherapy, Sichuan University, Chengdu, China.
7. Research Complex at Harwell, Rutherford Laboratory, Didcot, Oxfordshire OX11 0FA, UK.