Intermolecular pontentials: Interaction of water with lysozyme

Abstract

The interaction of water molecules with amino acids has been computed by performing a very large number of ab initio SCF LCAO MO computations (about 3000). A new type of interaction potential (formally resembling the Lennard-Jones potential with an added coulombic term) has been introduced to analytically describe in a simple way the computed interactions. This potential allows one to describe the interaction of water with many macromolecules, including enzymes and protein. As a first and preliminary example, we present the computation of the interaction of a water molecule with the enzyme lysozyme. Among the obtained results we note: (a) the complete generality of our method, that is noway restricted to the water-lysozyme system, (b) the possibility to provide a rigorous and quantitative definition to familiar concepts, as hydrophobicity and (c) the first visual representation of the shape of an enzyme as seen from a solvent (water), rather than from X-rays, the traditional representation up to date available. More in general, we are of the opinion to have provided evidence that, starting from ab initio computations, one can obtain reasonable intermolecular potentials to describe the interactions of chemical systems of remarkable complexity.