Figure 2From: Bacterial and human peptidylarginine deiminases: targets for inhibiting the autoimmune response in rheumatoid arthritis?Alignment of amino acid sequence of catalytic domains of Porphyromonas gingivalis PAD (PPAD) (residues 86 to 363), AIH from Dyadobacter fermentans DSM 18053 (locus Dfer_2630, residues 60 to 352), and human PAD4 (residues 306 to 556). Residues identical in PPAD and AIH and/or PAD4 are highlighted. Guanidino-binding (#) and catalytic residues (*) that are conserved in all families of guanidino-group modifying enzyme superfamily are indicated. The amino-terminal sequence of each enzyme is unique. In PAD4, the amino-terminal portion is folded into two consecutive immunoglobulin-like β-sandwich domains preceding the catalytic domain harboring the α/β-propeller fold [51]. A long 200-residue carboxy-terminal extension of PPAD is predicted to adopt an immunoglobulin-like β-sandwich structure [50]. AIH, agmatine iminohydrolase; PAD, peptidylarginine deiminase.Back to article page