1. Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, United Kingdom
2. Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester M1 7DN, United Kingdom
3. European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, F-38042 Grenoble, France