Fig. 5

Structural model of MtPPO7. The structural model of MtPPO7 was generated based on the crystal structure of a catechol oxidase from Aspergillus oryzae (AoCO4, Protein Data Bank entry: 4j3p) [42]. MtPPO7 and AoCO4 share an amino acid sequence identity of 38%. The MtPPO7 model is predominantly α-helical with the catalytic copper site situated in the four-helix bundle. The coordination of the two copper atoms (blue) by six histidine residues (orange) is strictly conserved. The three disulfide bridges Cys47-Cys398, Cys75-Cys134, and Cys196-Cys234 (yellow) are also conserved