Interaction of Ca2+ with mannose:: a density functional study

Five stable binding modes between Ca2+ and beta -o-mannose have been identified using hybrid density functional method. The most stable mode of binding involves the simultaneous interaction of Ca2+ with four oxygen atoms on the mannose, while some bidentate interactions are of comparable strength to the tridentate interaction, By partitioning the total interaction energy into "stabilization" and "deformation" energies, the effect of Ca2+-O bonding distances, intramolecular co-ordinate number, Ca hydrogen bonding and conformational strain upon complexation on the relative stability of different binding modes are analyzed. Biological relevance of our present study is also discussed. (C) 2001 Elsevier Science B.V. All rights reserved.