2,4'-Dihydroxyacetophenone dioxygenase (DAD), cupin domain
2,4'-Dihydroxyacetophenone dioxygenase (DAD) catalyzes the oxidation of 2,4'-dihydroxyacetophenone to 4-hydroxybenzoate and formate as part of the 4-hydroxyacetophenone catabolic pathway. This enzyme is a homo-tetramer containing one iron per molecule of enzyme. This enzyme is an unusual dioxygenase in that it cleaves a C-C bond in a substituent of the aromatic ring rather than within the ring itself. As a bacterial dioxygenase, DAD plays an important environmental role in the aerobic catabolism of aromatic compounds; expression of this enzyme in appropriately engineered microorganisms has the potential to use these aromatic pollutants as a carbon source and thus remove them from the environment. Proteins in this family belong to the cupin superfamily with a conserved "jelly roll-like" beta-barrel fold.
Feature 1: metal binding site [ion binding site], 3 residue positions
Conserved feature residue pattern:H H H
Evidence:
Structure:5BPX: Alcaligenes sp. 2,4'-dihydroxyacetophenone dioxygenase binds iron; contacts at 4.0A
Structure:3BAL: Acinetobacter johnsonii acetylacetone dioxygenase binds zinc; contacts at 4.0A
Comment:The metal binding site is usually a four-coordinate metallocenter that includes three histidines and one glutamate; however, proteins in this subfamily only contain three conserved metal-binding residues
Jiyao W et al.(2023). "The conserved domain database in 2023.",