Figure 2
PLC-β3 and RGS domains are structurally dissimilar, except for one asparagine residue in both partners that interacts similarly with Gαq. (a) The complex of Gαq with PLC-β3 (PDB ID: 3OHM). Gαq is shown as in Fig. 1b, PLC-β3 is shown as a magenta ribbon diagram. (b) Superimposition of the complexes of Gαq with RGS2 and RGS8 (PDB IDs: 4EKD and 5DO9, respectively). Gαq is shown as in panel a, RGS2 and RGS8 are shown as blue and light blue ribbon diagrams, respectively. (c) Superimposition of the complexes of Gαq with PLC-β3, RGS2 and RGS8, using only the coordinates of Gαq for the superimposition. One asparagine residue (“Asn”, namely Asn260/149/122 in PLC-β3/RGS2/RGS8) adopts the same orientation towards Gαq in all of these structures and interacts with Gαq similarly in all structures - in particular with the Gαq catalytic residue Gln209 (shown in sticks, with hydrogen bonds shown as dashed black lines).
