1. Department of Chemistry and Biochemistry, University of Maryland, 8051 Regents Drive, College Park, Maryland 20742, United States
2. Department of Molecular Medicine, and Department of Immunology & Microbiology, The Scripps Research Institute, La Jolla, California 92037, United States
3. Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, United States
4. Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, United States
5. Department of Chemistry and Department of Medical Microbiology and Immunology, University of Alberta, Edmonton T6G 2G2, Canada