From: New insights on unspecific peroxygenases: superfamily reclassification and evolution
Subfamily | Motif | aRoles of amino acids present in the motif | Hypothesized functions of the subfamily |
---|---|---|---|
I | FXD | Phe is basically involved in stacking interactions with other aromatic side-chains and the Asp is frequently involved in salt-bridges interacting with positively charged amino acids to create stabilizing H-bonds which can be important for protein’s stability. | may actively involve in interacting with aromatic residues and in forming stable H-bonds imparting to the structural stability. |
Cys-Cys | disulfide bond is mostly involved in providing stability to protein structure. | ||
II | RGN | Arg is frequently involved in making salt-bridges with the negatively charged amino acids creating stable H-bonds which may be crucial for the structure stability; the Gly provides the conformational stability, and the Asn is involved as protein’s active and binding sites. | may potentially interact with the hydrophobic ligands such as lipids and may show specificity for some polar substrates. |
IDG | Ile in the IDG motif is involved in recognizing hydrophobic ligands; Asp forms stable H-bonds with positively charged amino acids required for protein’s stability, and the Gly again may provide conformational stability. | ||
TXXXXXXR | Thr is often found in protein centers and capable of forming H-bonds with the polar substrates. | ||
III | G [ML]G | the Gly provides the conformational stability, Met and Leu plays a role in binding and recognition of hydrophobic ligands. | may play important role in substrate specificity/recognition and capable of forming strong H-bonds with the polar substrates. |
IV | CDA, FXXXDG, GAAXXXYE, and HXXF | Ala is involved in substrate recognition and specificity; Tyr makes stacking interactions with the aromatic side chains; His is involved in protein metal binding sites; and Phe also makes stacking interactions with aromatic side chains. | may show large interactions with the aromatic substrates and these motifs are perhaps involved in substrate recognition and binding. |
V | EDXXH | His is most commonly involved in active and binding sites especially in metal binding sites and the Asp and Glu residues create the stable H-bonds. | may play an important role in reacting with positively charged amino acids. |
GXG | Gly provides the conformational stability |