PfPP1 sequence comparison. The predicted sequences of Plasmodium PP1 (this study) and human PP1 alpha (P08129) catalytic subunits were aligned using the CLUSTALW program at the European Bioinformatics Institute (EMBL) server, and later refined by visual inspection. The amino acid residue numbers are shown on the right. Residues are marked as: non-conservative replacement (.); conservative replacement (:), and identical (*). Residues important in I-2 interaction are highlighted in gray: E52, E54; D164, E165, and K166.