ref 4 Rosenbaum et al., GPCR Engineering Yields High-Resolution Structural Insights into b2 Adrenergic Receptor Function. Science. 2007 Oct 25; PMID: 17962519
ref 5 Grace Cr., et al., Structure of the N-terminal domain of a type B1 G protein-coupled receptor in complex with a peptide ligand. Proc Natl Acad Sci U S A. 2007 Mar 20;104(12):4858-63. PMID: 17360332
ref 6 Sun, C., et al., Solution structure and mutational analysis of pituitary adenylate cyclase-activating polypeptide binding to the extracellular domain of PAC1-RS. Proc Natl Acad Sci U S A. 2007 May 8;104(19):7875-80. PMID: 17470806
ref 7 Parthier C et al., Crystal structure of the incretin-bound extracellular domain of a G protein-coupled receptor. Proc Natl Acad Sci U S A. 2007 Aug 28;104(35):13942-7. PMID: 17715056