FIGURE 6.

Differences in electron density observed within the GoLoco motif between WT and Q147L mutant Gα_i1·GDP/RGS14 GoLoco motif complexes. A crystal structure (using diffraction data to 2.38-Å resolution) of the Gα_i1^Q147L·GDP/RGS14 GoLoco motif complex (Protein Data Bank code 3ONW) was obtained. Overall, the Gα_i1^Q147L protein binds the RGS14 GoLoco motif protein similarly (root mean square deviation of 0.38 Å) to Gα_i1^WT (code 2OM2 (7)). However, electron density for the GoLoco motif peptide residues Gly-511, Ala-512, and His-513 is much weaker in the Gα_i1^Q147L structure (B) than in the WT structure (code 2OM2) (A), indicating disorder in the peptide surrounding the mutated Gα_i1 residue Leu-147. Both 2F_o − F_c electron density maps shown are contoured at σ = 1.5.