Fig. 1.

Overview of the GPR oligomeric structure and residues present at the cross-protomer interface. (A) Topological plot of GPR. The seven transmembrane helices (A-G), the signal sequence (red), and the positions of W34 (gray), H75, D97 (proton acceptor), and K231 (Schiff base; yellow) are labeled. Protons are transported from the intracellular to the extracellular side. (B) Overview of the residue positions in the pentamer and detailed structural arrangements of the interprotomer cluster consisting of W34 in one protomer (gray) and H75, D97, and pSB in the neighboring protomer (yellow). Data from PDB ID: 4JQ6 (7).