Figure 7
Multi-specificity analysis of Gαi residues contributing to interactions with RGSs and GoLoco motifs. (a) Structural regions in Gαi that can interact with its partners. Gαi is shown as a ribbon diagram colored light orange (GTPase domain) and gold (helical domain). The α3 helix and subsequent loop are colored maroon. The P-loop is colored magenta and the switch (Sw) regions are colored as follows: Sw I, teal; Sw II, blue; and Sw III, purple. The nucleotide is shown as balls and sticks, colored green. (b) Gαi1 residues that substantially contribute to interactions with high-activity RGS domains, shown as spheres and colored according to the type of energy contribution, as in Fig. 4. The following three crystal structures of Gαi1–RGS complexes (with PDB IDs) were superimposed: Gαi1–RGS1 (PDB ID: 2GTP), Gαi1–RGS4 (PDB ID: 1AGR), and Gαi1–RGS16 (PDB ID: 2IK8). Gαi subunits are shown as ribbon diagrams, colored according to Gα domains: teal (GTPase domain) and olive (helical domain). (c) Gαi1 residues that substantially contribute to interactions with GoLoco (GL) motifs, shown as spheres and colored as in panel b. The following three crystal structures of Gαi1–GoLoco complexes (with PDB IDs) were superimposed: Gαi1–GL-RGS14 (PDB ID: 2OM2), Gαi1–GL-LGN4 (PDB ID: 4G5Q), and Gαi3–GL-LGN3 (PDB ID: 4G5S). Gαi is visualized as a ribbon diagram, colored gold (GTPase domain) and light blue (helical domain). (d) Interactions of Gαi with GoLoco motifs versus RGS domains. Gαi residues that substantially contribute to the interactions are shown as spheres, colored according to the key. Gαi is visualized as a ribbon diagram, colored as in panel c.
