Structural Insights into the Process of GPCR-G Protein Complex Formation.
Liu, X., Xu, X., Hilger, D., Aschauer, P., Tiemann, J.K.S., Du, Y., Liu, H., Hirata, K., Sun, X., Guixa-Gonzalez, R., Mathiesen, J.M., Hildebrand, P.W., Kobilka, B.K.(2019) Cell 177: 1243-1251.e12
- PubMed: 31080070 
- DOI: https://doi.org/10.1016/j.cell.2019.04.021
- Primary Citation of Related Structures:  
6E67, 6EG8 - PubMed Abstract: 
The crystal structure of the β2-adrenergic receptor (β2AR) bound to the G protein adenylyl cyclase stimulatory G protein (Gs) captured the complex in a nucleotide-free state (β2AR-Gs empty ). Unfortunately, the β2AR-Gs empty complex does not provide a clear explanation for G protein coupling specificity. Evidence from several sources suggests the existence of a transient complex between the β2AR and GDP-bound Gs protein (β2AR-Gs GDP ) that may represent an intermediate on the way to the formation of β2AR-Gs empty and may contribute to coupling specificity. Here we present a structure of the β2AR in complex with the carboxyl terminal 14 amino acids from Gαs along with the structure of the GDP-bound Gs heterotrimer. These structures provide evidence for an alternate interaction between the β2AR and Gs that may represent an intermediate that contributes to Gs coupling specificity.
Organizational Affiliation: 
Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Medicine, Tsinghua University, Beijing 100084, China. Electronic address: liu_xy@mail.tsinghua.edu.cn.