Introduction

Abstract

The knowledge about conformation of proteins and distinct interactions between a ligand and it’s target protein is necessary to explain pharmacological data on a molecular level. Additionally, based on this knowledge, it may be possible to develop new, potent drugs more efficiently. But how get these insights on a molecular level? Several experimental techniques, like mutagenesis studies combined with pharmacological investigations may give hints about amino acids, being important for stability of a protein or being important for the interaction between ligand and protein. But these studies exhibit no information about energetics and hydrogenbond- networking for example. Other techniques, like determination of structures of proteins or protein-ligand-complexes by NMR or crystallography are very useful to obtain information about secondary, tertiary or quartary structures of proteins (http://www.pdb.org).