Anna Qiao / Shuo Han / Xinmei Li / Zhixin Li / Peishen Zhao / Antao Dai / Rulve Chang / Linhua Tai / Qiuxiang Tan / Xiaojing Chu / Limin Ma / Thor Seneca Thorsen / Steffen Reedtz-Runge / Dehua Yang / Ming-Wei Wang / Patrick M Sexton / Denise Wootten / Fei Sun / Qiang Zhao / Beili Wu /
PubMed 要旨
Class B G protein-coupled receptors, an important class of therapeutic targets, signal mainly through the G class of heterotrimeric G proteins, although they do display some promiscuity in G protein ...Class B G protein-coupled receptors, an important class of therapeutic targets, signal mainly through the G class of heterotrimeric G proteins, although they do display some promiscuity in G protein binding. Using cryo-electron microscopy, we determined the structures of the human glucagon receptor (GCGR) bound to glucagon and distinct classes of heterotrimeric G proteins, G or G These two structures adopt a similar open binding cavity to accommodate G and G The G binding selectivity of GCGR is explained by a larger interaction interface, but there are specific interactions that affect G more than G binding. Conformational differences in the receptor intracellular loops were found to be key selectivity determinants. These distinctions in transducer engagement were supported by mutagenesis and functional studies.