Figure 4: Structural and functional comparison of GtαCT and ArrFL-1.
From: Crystal structure of a common GPCR-binding interface for G protein and arrestin
(a) Side view of the active receptor Ops* crevice (black ribbons and sticks) with bound GtαCT-HA peptide (blue ribbon and sticks; PDB entry 3DQB). (b) Side view of the active receptor Ops* crevice (orange ribbons and sticks) with bound ArrFL-1 peptide (purple ribbon and sticks). (c) Stabilization of Meta II by the high-affinity peptide GtαCT-HA and (d) ArrFL-1 peptide. (e) Competition against rod photoreceptor arrestin for binding to phosphorylated opsin by GtαCT-HA and (f) ArrFL-1 peptide. In panels c–f, data points from independent experiments are represented as differently shaped symbols. The peptide titration experiments which measure Meta II-stabilization (c,d and Supplementary Fig. 9a,b,c) yield an apparent KD, from which the true KD value of peptide binding to Meta II can be derived. Further experimental details are given in the Methods.
