1 London Centre for Nanotechnology, University College London, London, United Kingdom; Institute of Structural and Molecular Biology, University College London, London, United Kingdom.
2 London Centre for Nanotechnology, University College London, London, United Kingdom; Department of Crystallography/Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck College, London, United Kingdom.
3 Department of Crystallography/Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck College, London, United Kingdom.
4 London Centre for Nanotechnology, University College London, London, United Kingdom; Institute of Structural and Molecular Biology, University College London, London, United Kingdom; Department of Physics and Astronomy, University College London, London, United Kingdom. Electronic address: [email protected].