InterPro domain: IPR006094

Various enzymes use FAD as a co-factor, most of these enzymes are oxygen-dependent oxidoreductases, containing a covalently bound FAD group which is attached to a histidine via an 8-alpha-(N3-histidyl)-riboflavin linkage. One of the enzymes Vanillyl-alcohol oxidase (VAO, 1.1.3.38 ) has a solved structure, the alignment includes the FAD binding site, called the PP-loop, between residues 99-110 [ 1 ]. The FAD molecule is covalently bound in the known structure, however the residue that links to the FAD is not in the alignment. VAO catalyses the oxidation of a wide variety of substrates, ranging from aromatic amines to 4-alkylphenols. Other enzymes included in this family are MurB family members UDP-N-acetylenolpyruvoylglucosamine reductases involved in the biosynthesis of peptidoglycan [ 2 ], D-lactate dehydrogenases among many others oxidoreductases.

1. Structural analysis of flavinylation in vanillyl-alcohol oxidase. J. Biol. Chem. 275, 38654-8
2. The structure of the substrate-free form of MurB, an essential enzyme for the synthesis of bacterial cell walls. Structure 4, 47-54