1. Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, U.K.
2. NMR Platform, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, U.K.
3. Chemistry Platform, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, U.K.
4. Isomerase, Chesterford Research Park, Cambridge CB10 1XL, U.K.