Fig. 3. Alignment of the amino acid sequence of the CatD of AoChi with known three-dimensional structures of GH19 chitinases from plants. The CatD sequence of AoChi was aligned to GH19 structures from: Carica papaya (PDB ID: 3CQL), Vigna unguiculata subsp. sesquipedalis (PDB ID: 4TX7), Secale cereale (PDB ID: 4DWX), Hordeum vulgare (PDB ID: 2BAA), Oryza sativa subsp. japonica (PDB ID: 2DKV), Canavalia ensiformis (PDB ID: 1DXJ), Brassica juncea (PDB ID: 2Z37), Cryptomeria japonica (PDB ID: 5H7T) and Picea abies (PDB ID: 3HBD). Sites containing residues involved in catalysis (triangles) and substrate-binding (hash marks) are indicated. Disulfide bonds, as observed in the three-dimensional model of AoChi (Fig. 7), are indicated by orange lines. Loop regions (I–V), as assigned by Taira et al. (Taira et al., 2011), are boxed. Loop VI (this work), which is present only in AoChi and other class VI chitinases, is also boxed. Alignment columns are colored according to the ALSCRIPT Calcons convention, as implemented in ALINE (Bond and Schüttelkopf, 2009), using a predefined color scheme, which reflects the conservation of amino acid properties in each column (dark blue: identical residues; white: dissimilar residues). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)