Interactions and Geometry of Aromatic Side Chains in Globular Proteins

Nick Dedes, G. & Stavroula Koulocheri, A.^*

Department of Biological Chemistry, Medical School, University of Athens, Greece

Dr. Stavroula Koulocheri, A., Department of Biological Chemistry, Medical School, University of Athens, Greece.

Keywords: Noncovalent Interactions; Arenes; Hydrogen Bonds; Proteins

Abstract

It is known that the traditionally noncovalent interactions like charge-charge interactions, hydrogen bonding, dipolar interactions, London forces and the hydrophobic effect, thought to contribute to the net free energy of stabilization of protein structure and folding, have been appreciated for many years. This is due to their role in protein structure stabilization, ligand -protein interactions and in molecular recognition phenomena. Recently, it has become clear that this is not the whole story. A new class of interactions in proteins involving weakly polar aromatic aminoacid side chains has been observed and characterized. Intermolecular interactions involving arenes are considered specific, with enthalpic contribution, and their importance is defined by their commonality, strength, conservation, and many functions. This review attempts to describe chemically these interactions involving aromatic rings with the respect to protein structure and conformational stability.
Topics addressed are cation-?, arene-arene interactions, hydrogen bonding to ? systems, as well as sulfur-aromatic interactions. The geometric pattern and the energetic profile of these weak contacts are also discussed.

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