Olfactory receptor amino acid sequence alignment. The amino acid sequences of the open reading frame of the three FMF region olfactory receptor genes are shown. These sequences are aligned with those of prototypic members of the 2C (olf3–MUS) and 1F (or5–RAT) subfamilies. Amino acid residues present in more than one clone at a given position are shaded. Highly conserved residues, including two cysteines (•), a serine (○), and a SY and MAYDRFVAVC sequence motif (underlined), thought to be involved in OR structure or function are indicated. The seven hydrophobic putative transmembrane-spanning domains are demarcated and numbered with Roman numerals.