1. School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
2. NTU Institute of Structural Biology, Nanyang Technological University, 59 Nanyang Drive, Singapore 636921, Singapore
3. Umeå Centre for Electron Microscopy, Umeå University, Chemical Biological Centre (KBC) Building, Linnaeus väg 6, SE-90736 Umeå, Sweden