InterPro domain: IPR015920

Cellobiose dehydrogenase (CHD; 1.1.99.18 ) is found in a variety of fungi, including white rot, brown rot and plant pathogen fungi. The enzyme is extracellular flavocytochrome that degrades both cellulose and lignin. Specifically, CDHs oxidize cellobiose, cellodextrins, and lactose to corresponding lactones, utilizing a variety of electron acceptors [ 1 ]. It acts as a monomer consisting of two domains: a cytochrome domain containing a b-type haem, which is linked through a peptide linker to a large flavodehydrogenase domain containing FAD as a cofactor [ 2 ].

This entry represents the b-type cytochrome domain. This domain assumes an immunoglobulin-like beta-sandwich fold consisting of 7 beta-strands in 2 sheets with a Greek key topology; the haem iron is ligated by a Met/His couple and is docked at the exterior of the enzyme [ 3 ]. It is found at the N terminus of these enzymes, and belongs to the DOMON domain superfamily, a ligand-interacting motif found in all three kingdoms of life [ 4 ].

1. Cellobiose dehydrogenase--a flavocytochrome from wood-degrading, phytopathogenic and saprotropic fungi. Curr. Protein Pept. Sci. 7, 255-80
2. Cellobiose dehydrogenase from the fungi Phanerochaete chrysosporium and Humicola insolens. A flavohemoprotein from Humicola insolens contains 6-hydroxy-FAD as the dominant active cofactor. J. Biol. Chem. 274, 3338-44
3. A new scaffold for binding haem in the cytochrome domain of the extracellular flavocytochrome cellobiose dehydrogenase. Structure 8, 79-88
4. The DOMON domains are involved in heme and sugar recognition. Bioinformatics 23, 2660-4