FIGURE 1.

(A) Sequence alignment using Boxshade of representative mammalian (human, chimpanzee, rat, mouse, platypus) and representative lower vertebrate RXFP3 sequences (Frog and Zebrafish) compared to human RXFP4. Only residues from the extracellular N-terminus and extracellular loops (ELs) are shown and the N-terminus is aligned from amino acid 34 of human RXFP3. All the glutamic (E) and aspartic acid (D) residues in the extracellular domain are highlighted with those conserved in RXFP3 and RXFP4 in yellow and those conserved in RXFP3 only in red. Conserved potential N-glycosylation sites are highlighted in green. Highly conserved amino acids across all species are boxed in black and conservative amino acid substitutions are boxed and shaded. (B) Human relaxin-3 peptide sequence with the key B-chain residues involved in receptor binding and activation highlighted.