STRUCTURAL AND ENERGETIC ASPECTS OF PROTEIN-PROTEIN RECOGNITION

Specific recognition between proteins plays a crucial role in a great number of vital processes. In this review different types of protein-p rotein complexes are analyzed on the basis of their three-dimensional structures which became available in recent years. The complexes which are analyzed include: those resulting from different types of recogni tion between proteinase and protein inhibitor (canonical inhibitors of serine proteinases, hirudin, inhibitors of cysteine proteinases, carb oxypeptidase inhibitor), barnase-barstar, human growth hormone-recepto r and antibody-antigen. It seems obvious that specific and strong prot ein-protein recognition is achieved in many different ways. To further explore this question, the structural information was analyzed togeth er with kinetic and thermodynamic data available for the respective co mplexes. It appears that the energy and rates of specific recognition of proteins are influenced by many different factors, including: area of interacting surfaces; complementarity of shapes, charges and hydrog en bonds; water structure at the interface; conformational changes; ad ditivity and cooperativity of individual interactions, steric effects and various (conformational, hydration) entropy changes.