1. MRC-Laboratory for Molecular and Cell Biology, University College London, London, WC1E 6BT, UK
2. Institute of Physics of Living Systems, University College London, WC1E 6BT, UK
3. Centre for Mathematics, Physics, and Engineering in the Life Sciences and Experimental Biology, University College London, London, WC1E 6BT, UK
4. Department of Genetics, Evolution and Environment, University College London, London, WC1E 6BT, UK
5. Howard Hughes Medical Institute, Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
6. London Centre for Nanotechnology, University College London, London, WC1E 6BT, UK
7. Department of Cell and Developmental Biology, University College London, WC1E 6BT, UK