HINGE-BENDING IN L-ARABINOSE-BINDING PROTEIN - THE VENUS-FLYTRAP MODEL

Abstract

Theoretical conformational energy calculations show that large changes in the width of the binding-site cleft in the Escherichia coli L-arabinose-binding protein involve only modest changes in the protein internal energy. Solvation energy changes associated with such variations of the cleft width and with protein-ligand interactions are estimated to be significantly larger than the internal energy changes. The binding-site cleft is open in the unliganded protein and is induced to close on ligation. This picture is consistent with experimental data on the structure and binding kinetics of the L-arabinose-binding protein and provides a physical framework for interpreting such data.