A simple shape characteristic of protein-protein recognition

Motivation: Observation of co-crystallized protein-protein complexes and low-resolution protein-protein docking studies suggest the existence of a binding-related anisotropic shape characteristic of protein-protein complexes. Results: Our study systematically assessed the global shape of proteins in a non-redundant database of co-crystallized protein-protein complexes by measuring the distance of the surface residues to the protein's center of mass. The results show that on average the binding site residues are closer to the center of mass than the non-binding surface residues. Thus, the study directly detects an important and simple binding-related characteristic of protein shapes. The results provide an insight into one of the fundamental properties of protein structure and association.