1. Iceni Diagnostics The Innovation Centre Norwich Research Park Norwich Norfolk NR4 7GJ UK
2. Department of Biological ChemistryJohn Innes Centre Norwich Research Park Norwich Norfolk NR4 7UH UK
3. Present address: Cobra Biologics, Science ParkUniversity of Keele Newcastle-under-Lyme Staffordshire ST5 5SP UK
4. Medicinal ChemistryMedicines Research CentreGlaxoSmithKline Stevenage Hertfordshire SG1 2NY UK
5. Present address: Department of Chemistry and Manchester Institute of BiotechnologyUniversity of Manchester Manchester M1 7DN UK