|
| Figure 5: Structure of GPCRs. All GPCRs share a common membrane topology consisting of an NH2-terminal extracellular domain, seven transmembrane α helices joined by three ECL and ICL and an intracellular COOH-terminal domain. Red circles denote conserved residues. (A) The Family A GPCRs contain a disulphide bridge that connects ECL1 and ECL2 causing the receptor to ‘kink’ and ‘tilt’. The C-terminal domain contains a conserved palmitoylated cysteine residue. (B) The Family B GPCRs are characterized by a long N-terminal tail consisting of many conserved disulphide bonds. (C) The Family C GPCRs have very large N and C- terminal domains with an agonist binding domain described as a ‘venus fly trap’ located at the N- terminus. Additionally, a conserved disulphide bridge connects ECL1 and ECL2 and a short and conserved ICL3 also define family C GPCRs. |
