1. Centre for Cell Imaging, School of Biological Sciences, Bioscience Research Building, Crown Street, Liverpool, L69 7ZB, UK.
2. Department of Chemistry, University of Manchester Institute of Science and Technology, P.O. Box 88, Sackville Street, Manchester, M60 1QD, UK.
3. Department of Mathematics, University of Manchester Institute of Science and Technology, P.O. Box 88, Sackville Street, Manchester, M60 1QD, UK.
4. Royal Liverpool Children's National Health Service Trust, Alder Hey Hospital, Eaton Road, Liverpool, L12 2AP, UK.
5. Molecular Biology Department, AstraZeneca Research and Development Charnwood, Bakewell Road, Loughborough, Leicestershire, LE11 5RH, UK.