1. Nanoscience Centre, University of Cambridge, 11 JJ Thomson Avenue, Cambridge CB3 0FF, United Kingdom
2. Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
3. Institute for Research in Biomedicine, Baldiri Reixac 10, 08028 Barcelona, Spain
4. Centre for Protein Engineering, University of Liège, Sart Tilman, 4000 Liège, Belgium
5. Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010 Barcelona, Spain