1. School of Molecular and Cellular Biology, Astbury Centre for Structural Molecular Biology and Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, U.K.
2. Institute of Chemical Biology, Department of Chemistry, Imperial College London, London SW7 2AZ, U.K.
3. School of Chemistry, Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K.