Angiotensin and biased analogs induce structurally distinct active conformations within a GPCR.
Wingler, L.M., Skiba, M.A., McMahon, C., Staus, D.P., Kleinhenz, A.L.W., Suomivuori, C.M., Latorraca, N.R., Dror, R.O., Lefkowitz, R.J., Kruse, A.C.(2020) Science 367: 888-892
- PubMed: 32079768 
- DOI: https://doi.org/10.1126/science.aay9813
- Primary Citation of Related Structures:  
6OS0, 6OS1, 6OS2 - PubMed Abstract: 
Biased agonists of G protein-coupled receptors (GPCRs) preferentially activate a subset of downstream signaling pathways. In this work, we present crystal structures of angiotensin II type 1 receptor (AT1R) (2.7 to 2.9 angstroms) bound to three ligands with divergent bias profiles: the balanced endogenous agonist angiotensin II (AngII) and two strongly β-arrestin-biased analogs. Compared with other ligands, AngII promotes more-substantial rearrangements not only at the bottom of the ligand-binding pocket but also in a key polar network in the receptor core, which forms a sodium-binding site in most GPCRs. Divergences from the family consensus in this region, which appears to act as a biased signaling switch, may predispose the AT1R and certain other GPCRs (such as chemokine receptors) to adopt conformations that are capable of activating β-arrestin but not heterotrimeric G q protein signaling.
Organizational Affiliation: 
Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA.