Raints that accompany GPCR activation occurs (Choe et al., 2011; Rasmussen et al., 2011; Standfuss et al., 2011; Xu et al., 2011). Upon examination of the antibody-agonist2-adrenergic receptor structure, larger-scale displacements of helices H-V and H-VI are evident compared with the small-scale displacements in the 1-adrenergic receptor structures. It remains unclear as to how to dissect the rela