Domain architectures of selected examples of polymorphic toxins containing distinct releasing peptidases: (A) HINT, (B) ZU5, (C) PrsW peptidase, (D) Caspase peptidase, (E) MCF1-SHE-like predicted peptidase. The alignment of MCF1-SHE domain is shown with predicted catalytic residues marked with blue asterisks. For all alignments in this study, proteins are denoted by their gene name, species abbreviations and GI (Genbank Index) numbers separated by underscores. Secondary structure assignments are shown above the alignment, where the blue arrow represents the β-strand and the red cylinder the α-helix. Poorly conserved inserts are excluded in the alignment and replaced by the length of the inserts. Columns in the alignment are colored based on their amino acid conservation at consensus shown below the alignment. The coloring scheme and consensus abbreviations are as follows: h, hydrophobic (ACFILMVWY), l, aliphatic (LIV) and a, aromatic (FWY) residues shaded yellow; b, big residues (LIYERFQKMW), shaded gray; s, small residues (AGSVCDN) and u, tiny residues (GAS), shaded green; p, polar residues (STEDKRNQHC) shaded blue; and c, charged residues (DEHKR) shaded magenta. Absolutely conserved residues are shaded red.