Molecular insights into ago-allosteric modulation of the human glucagon-like peptide-1 receptor.
Cong, Z., Chen, L.N., Ma, H., Zhou, Q., Zou, X., Ye, C., Dai, A., Liu, Q., Huang, W., Sun, X., Wang, X., Xu, P., Zhao, L., Xia, T., Zhong, W., Yang, D., Eric Xu, H., Zhang, Y., Wang, M.W.(2021) Nat Commun 12: 3763-3763
- PubMed: 34145245 
- DOI: https://doi.org/10.1038/s41467-021-24058-z
- Primary Citation of Related Structures:  
7DUQ, 7DUR, 7E14, 7EVM - PubMed Abstract: 
The glucagon-like peptide-1 (GLP-1) receptor is a validated drug target for metabolic disorders. Ago-allosteric modulators are capable of acting both as agonists on their own and as efficacy enhancers of orthosteric ligands. However, the molecular details of ago-allosterism remain elusive. Here, we report three cryo-electron microscopy structures of GLP-1R bound to (i) compound 2 (an ago-allosteric modulator); (ii) compound 2 and GLP-1; and (iii) compound 2 and LY3502970 (a small molecule agonist), all in complex with heterotrimeric G s . The structures reveal that compound 2 is covalently bonded to C347 at the cytoplasmic end of TM6 and triggers its outward movement in cooperation with the ECD whose N terminus penetrates into the GLP-1 binding site. This allows compound 2 to execute positive allosteric modulation through enhancement of both agonist binding and G protein coupling. Our findings offer insights into the structural basis of ago-allosterism at GLP-1R and may aid the design of better therapeutics.
Organizational Affiliation: 
School of Pharmacy, Fudan University, Shanghai, China.