Amino acid sequence alignment of selected human and viral PYDs. Listed are the PYDs of human ASC (Swiss-Prot Q9ULZ3), human POP1 (Q8WXC3), human Cryo (Q96P20), human Pyrin (O15553), human POP2 (Q56P42), human NALP1 (Q9C000), human NALP2 (Q9NX02), human NALP5 (P59047), human NALP7 (Q8WX94), human AIM2 (O14862), rabbit fibroma virus GP013L_PYD (Q9Q957), myxoma virus M013L_PYD (Q9Q8S8), and swinepox virus SPV013 (Q8V3S3).