1. Manchester Institute of Biotechnology, School of Chemistry, University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
2. Department of Molecular and Cell Biology and Leicester Institute of Structural and Chemical Biology, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 7RH, U.K.
3. School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, U.K.
4. School of Chemistry, Cantock’s Close, Bristol BS8 1TS, U.K.