Fig. 5.

Molecular interactions within the TM6/ECL3/TM7-TM1/TM3/ECL2/TM5 interfaces of GIPR, SV1, and SV2. (A) The extracellular halves of TM6 of both SV1 and SV2 fold inward to form massive polar and nonpolar interactions with TM3, ECL2, and TM5. The structures of SV1 and SV2 are superimposed on the GIP-bound GIPR (PDB code: 7DTY) using the Cα carbons of the TMD residues. (B) The ECL3 and extracellular half of TM7 of SV1 and SV2 are clasped by TM1, TM3 and ECL2 with the formation of multiple contacts.