Empirical parameters for estimating protein-protein binding energies: number of short- and long-distance atom-atom contacts.

The number of atom-atom contacts in long distance can fit to the experimental binding energies in a dataset containing 151 experimental data with the correlation coefficient about 0.68. Based on this factor, a set of distance-dependent empirical potentials for various types of short-distance (2.4 A-5 A) contacts was obtained by guided fitting, i.e. a set of two parameters fitting. Incorporation of these short-distance potentials improved the correlation coefficients to 0.881.