1 Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK.
2 Interdisciplinary Nanoscience Centre (iNANO), Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark. Electronic address: dao@inano.au.dk.
3 Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK. Electronic address: S.e.radford@leeds.ac.uk.