Structural Studies on Flavin Reductase PheA2 Reveal Binding of NAD in an Unusual Folded Conformation and Support Novel Mechanism of Action

The catabolism of toxic phenols in the thermophilic organism Bacillus thermoglucosidasius A7 is initiated by a two-component enzyme system. The smaller flavin reductase PheA2 component catalyzes the NADH-dependent reduction of free FAD according to a ping-pong bisubstrate-biproduct mechanism. The reduced FAD is then used by the larger oxygenase component PheA1 to hydroxylate phenols to the corresponding catechols. We have determined the x-ray structure of PheA2 containing a bound FAD cofactor (2.2 Angstrom), which is the first structure of a member of this flavin reductase family. We have also... Mehr ...