1. Division of Molecular Medicine Bose Institute, P-1/12, C.I.T. Scheme VII M Kolkata 700054 India
2. Current address: Unité de Chimie des Biomolécules Institut Pasteur 25/28 Rue du Docteur Roux Paris Cedex 15 75724 France
3. Center for Vaccine Development and Global Health University of Maryland School of Medicine Baltimore MD 21201-1509 USA
4. Department of Chemistry Michigan State University 578 South Shaw Lane East Lansing MI 48824 USA
5. Institute for Quantitative Health Science & Engineering Michigan State University 578 South Shaw Lane East Lansing MI 48824 USA
6. Department of Biomedical Engineering Michigan State University East Lansing MI 48824 USA