1. Institut Européen de Chimie et Biologie Université de Bordeaux 2 rue Robert Escarpit 33607 Pessac France
2. Institut des Sciences Moléculaires CNRS UMR5255 33405 Talence France
3. Department of Biochemistry and Molecular Biology University of Georgia Athens GA 30602 USA
4. Complex Carbohydrate Research Center University of Georgia Athens GA 30602 USA