Figure 3.

Sequence alignment of six maximally divergent representatives of the PC synthase family, AtPCS1, A. yokoscense PCS1 (AyPCS1), CePCS1, SpPCS, NsPCS, and M. degradans PC synthase homolog (shown with standard gene product acronym or species name and GenBank ID) with three papain superfamily Cys proteases, papain, cruzain, and staphopain (shown with PDB code). The Cys proteases are shown in structural alignment. Within the groups of Cys protease and PC synthase family members, highly conserved positions are shown in bold type and invariant residues are shown on a gray background. Positions conserved across all of the sequences are shown in white type on a black background. The amino acid residue numbering and actual secondary structure for staphopain A are shown above the alignment. The residue numbering and predicted secondary structure for AtPCS1 are shown below the alignment. Cylinders, α-helix; arrows, β-sheet. Significant structural insertions present in papain and cruzain, versus staphopain A, are shown as X, where X is the insertion length (individual residues not shown). Shown here is the complete alignment of which portions were depicted schematically in Figure 2 of Rea et al. (2004).