1. Chemical Glycobiology Laboratory, The Francis Crick Institute, NW1 1AT London, UK
2. Department of Chemistry, Imperial College London, W12 0BZ London, UK
3. Tumour-Host Interaction Laboratory, The Francis Crick Institute, NW1 1AT London, UK
4. Department of Chemistry, Yale University, CT 06511 New Haven, USA
5. Vertex Pharmaceuticals (Europe) Ltd., 86-88 Jubilee Avenue, Milton Park, Abingdon, OX14 4RW Oxfordshire, UK