1. Molecular Modelling Group, Indian Institute of Chemical Technology, Hyderabad 500‐607 (India), Fax: (+91) 40‐27193016
2. The Manchester Interdisciplinary Biocentre and the School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN (UK), Fax: (+44) 161‐3065201