Crystal Structure of the PAC1R Extracellular Domain Unifies a Consensus Fold for Hormone Recognition by Class B G-Protein Coupled Receptors
Figure 4
Superimposition of PAC1R/VIP2R and PAC1R X-ray and NMR structures.
(a) the C-terminal portion of PAC1R (green) and VIP2R (blue) depicts the expected similarity in (i) the backbone and (ii) the position of the conserved residues. (b)(i) Superimposition of the backbone of the X-ray (green) and NMR (magenta) structures of the PAC1R ECD. The two molecules were aligned using Pymol and laterally separated (ii) the close up of selected residues in the two structures. Note the unexpected dissimilarity in the position of the conserved residues and near the C77–C118 disulphide linkage, which would warrant its disruption to allow such massive displacement in solution. Furthermore, the region around Pro78 is very different between the X-ray and NMR structures. However, this region of the X-ray PAC1R structure and the VIP2R structure superimposes well and shows the expected conformational similarity.