Identifying G protein-coupled receptor dimers from crystal packings

Dimers of G protein-coupled receptors are believed to be important for signaling with their associated G proteins. Low resolution electron microscopy shows rhodopsin dimers in native retinal membranes, and CXCR4 dimers are found in several different crystal structures. Evidence for dimers of other GPCRs is more indirect. An alternative to computational modeling studies is to search for parallel dimers in the packing environments of the reported crystal structures of GPCRs. Two major structural types of GPCR dimers exist (as predicted by others), but there is considerable structural variation within each cluster. The different structural variants described here might reflect different functional properties and should provide a range of model structures for computational and experimental examination.SynopsisAnalysis of intermolecular interactions in G protein-coupled receptor crystal structures shows two major types of dimers.