1. Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
2. Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
3. Department of Chemistry, University of Cambridge Lensfield Road, Cambridge CB2 1EW, UK
4. Bioscience Technology Facility, Department of Biology, University of York, York YO10 5DD, UK