Conformational dynamics of the activated GLP-1 receptor-Gs complex revealed by cross-linking mass spectrometry and integrative modeling

ABSTRACT: Despite revolutionary advancements in GPCR structural biology, our understanding of the complexity of GPCR activation and signaling would not be complete without complementary information on the conformational dynamics. Yet it is particularly challenging to study the dynamics of GPCR complexes with their signaling partners due to their transient nature, short living time, and low stability. Here, by combining cross-linking mass spectrometry with integrative modeling, we establish a new approach to portray the alternative conformational ensemble of an activated GPCR-G protein complex at atomic resolution. The integrative structures generated in our study describe heterogeneous conformations for a high number of potential alternative active states for the GLP-1 receptor-Gs complex, which show marked differences from its cryo-EM structure, especially at the receptor-Gs interface and inside Gs heterotrimer. Alanine-scanning mutagenesis coupled with pharmacological assays validates the functional impact of 24 interface residue contacts only observed in the integrative structures yet absent in the cryo-EM structure. Our study provides a unique framework through integrating spatial connectivity data with structural modeling to characterize the conformational dynamics of GPCR signaling complexes.

ORGANISM(S): Homo Sapiens

SUBMITTER: Wenqing Shui  

PROVIDER: PXD039315 | iProX | Sun Jan 08 00:00:00 GMT 2023

REPOSITORIES: iProX