Structure versus function-The impact of computational methods on the discovery of specific GPCR-ligands

Over the past decades, computational methods have become invaluable for drug design campaigns but also as auxiliary tool for structural biology. The combination of experimental and in silico methods in the field of G protein coupled receptors (GPCRs) is indispensable. Despite recent groundbreaking achievements in GPCR crystallography, structural information for the vast majority of this physiologically important protein class is only accessible through homology models. Since the understanding of the conformational changes resulting in multiple activation pathways is incomplete, the design of specific GPCR modulating drugs remains a major challenge. However, due to the highly interdisciplinary requirements for the investigation of receptor function and the necessity of joining scientist from different fields, computational approaches gain importance in rationalizing and illustrating certain specific effects. In silico methods, such as molecular dynamics (MD) simulations, pharmacophore modeling or docking, proved to be suitable to complement experimental approaches. In this review, we highlight recent examples of in silico studies that were successfully applied in the field of GPCR research. Those approaches follow two main goals: Firstly, structural investigations that help to understand the receptor function and the characterization of ligand binding and secondly the identification of novel GPCR modulators as potential drugs.