Figure 3.

Domain analysis of human DRD2Longer and C. elegans DOP-2XL dopamine receptors. (A) Schematic representation of receptor domains. DRD2Longer and CeDOP-2XL intracellular loop (il) are represented as blue shaded boxes and N_t and C_t are shown as green and red boxes, respectively. The numbers indicate the position of each intracellular loop in both the receptors. DOP-2XL il₃ (224-766 aa) consists of 546 amino acid residues that is more than 3 times the length of DRD2 il₃ (214-374 aa) with 160 amino-acid length. il₁and il₂ were almost comparable in size with less than 10 amino-acid difference. (B) Sequence comparison of receptor domains. Sequence alignment of DOP-2XL (WormBase accession no WP:CE45633) and DRD2Longer (UniProt accession no P14416-3) was performed based on their predicted GPCR structures. The domains used for alignment were il₂ and il₃ (il₃N) & (il₃C) regions found to be necessary for Gi coupling.