1. G Protein Coupled Receptors Tim Hulsen & David Lutje Hulsik

2. seven transmembrane regions hydrophobic/ hydrophilic domains conserved residues and motifs (i.e. NPXXY)

3. Major research difficulties Residue numbering: Schwartz / Baldwin (e.g. V.16) Ballesteros-Weinstein (e.g. 6.50) High-resolution structural information

4. Many possible methods mutation studies spinlabel NMR cystein scanning protease studies photoaffinity

5. Novel approaches (1) Turcatti et al. (1996): introducing unnatural amino acids at known sites by suppression of UAG nonsense codons with the aid of a chemically misacetylated synthetic tRNA  determination of distances by measuring the fluorescence resonance energy transfer (FRET) between the fluorescent unnatural amino acids  defining of structure

6. Novel approaches (2) Gröbner, G. et al. (2000): determination of three-dimensional structure using a new high-resolution solid-state NMR method: deuterium ( 2 H) NMR in combination with the magic angle oriented sample spinning (MAOSS) approach.