1. CIISA, Faculdade de Medicina Veterinária, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
2. The Complex Carbohydrate Research Center, The University of Georgia, 315 Riverbend Road, Athens, Georgia 30602
3. York Structural Biology Laboratory, Department of Chemistry, The University of York, York, YO10 5YW, U.K.
4. Institute of Cellular and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, U.K.
5. Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, U.K.
6. Architecture et Fonction des Macromolécules Biologiques, UMR6098, CNRS, Universités Aix-Marseille I & II, Case 932, 163 Avenue de Luminy, 13288 Marseille cedex 9, France