Structural Basis of the Activation of Heterotrimeric Gs-Protein by Isoproterenol-Bound beta 1 -Adrenergic Receptor.
Su, M., Zhu, L., Zhang, Y., Paknejad, N., Dey, R., Huang, J., Lee, M.Y., Williams, D., Jordan, K.D., Eng, E.T., Ernst, O.P., Meyerson, J.R., Hite, R.K., Walz, T., Liu, W., Huang, X.Y.(2020) Mol Cell 80: 59
- PubMed: 32818430 
- DOI: https://doi.org/10.1016/j.molcel.2020.08.001
- Primary Citation of Related Structures:  
7JJO - PubMed Abstract: 
Cardiac disease remains the leading cause of morbidity and mortality worldwide. The β 1 -adrenergic receptor (β 1 -AR) is a major regulator of cardiac functions and is downregulated in the majority of heart failure cases. A key physiological process is the activation of heterotrimeric G-protein Gs by β 1 -ARs, leading to increased heart rate and contractility. Here, we use cryo-electron microscopy and functional studies to investigate the molecular mechanism by which β 1 -AR activates Gs. We find that the tilting of α5-helix breaks a hydrogen bond between the sidechain of His373 in the C-terminal α5-helix and the backbone carbonyl of Arg38 in the N-terminal αN-helix of Gα s . Together with the disruption of another interacting network involving Gln59 in the α1-helix, Ala352 in the β6-α5 loop, and Thr355 in the α5-helix, these conformational changes might lead to the deformation of the GDP-binding pocket. Our data provide molecular insights into the activation of G-proteins by G-protein-coupled receptors.
Organizational Affiliation: 
Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, NY 10065, USA.