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 Nt and Ct 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.
Pandey and Harbinder Journal of Molecular Signaling 2012 7:3 doi:10.1186/1750-2187-7-3