title: Characterization of a novel PQQ-dependent quinohemoprotein pyranose dehydrogenase from Coprinopsis cinerea classified into auxiliary activities family 12 in carbohydrate-active enzymes.
abstract: The basidiomycete Coprinopsis cinerea contains a quinohemoprotein (CcPDH named as CcSDH in our previous paper), which is a new type of pyrroloquinoline-quinone (PQQ)-dependent pyranose dehydrogenase and is the first found among all eukaryotes. This enzyme has a three-domain structure consisting of an N-terminal heme b containing a cytochrome domain that is homologous to the cytochrome domain of cellobiose dehydrogenase (CDH; EC 1.1.99.18) from the wood-rotting basidiomycete Phanerochaete chrysosporium, a C-terminal family 1-type carbohydrate-binding module, and a novel central catalytic domain containing PQQ as a cofactor. Here, we describe the biochemical and electrochemical characterization of recombinant CcPDH. UV-vis and resonance Raman spectroscopic studies clearly reveal characteristics of a 6-coordinated low-spin heme b in both the ferric and ferrous states, as well as intramolecular electron transfer from the PQQ to heme b. Moreover, the formal potential of the heme was evaluated to be 130 mV vs. NHE by cyclic voltammetry. These results indicate that the cytochrome domain of CcPDH possesses similar biophysical properties to that in CDH. A comparison of the conformations of monosaccharides as substrates and the associated catalytic efficiency (kcat/Km) of CcPDH indicates that the enzyme prefers monosaccharides with equatorial C-2, C-3 hydroxyl groups and an axial C-4 hydroxyl group in the 1C4 chair conformation. Furthermore, a binding study shows a high binding affinity of CcPDH for cellulose, suggesting that CcPDH function is related to the enzymatic degradation of plant cell wall.
authors: Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Tokyo, Japan.
authors: Kouta
authors: K
authors: Takeda
authors: Department of Biomaterials Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors: Hirotoshi
authors: H
authors: Matsumura
authors: Department of Biomaterials Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors: Takuya
authors: T
authors: Ishida
authors: Department of Biomaterials Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors: Masahiro
authors: M
authors: Samejima
authors: Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Tokyo, Japan.
authors: Hiroyuki
authors: H
authors: Ohno
authors: Department of Environmental and Natural Resource Science, Tokyo University of Agriculture and Technology, Tokyo, Japan.
authors: Makoto
authors: M
authors: Yoshida
authors: Department of Biomaterials Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors: Kiyohiko
authors: K
authors: Igarashi
authors: Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Tokyo, Japan.
authors: Nobuhumi
authors: N
authors: Nakamura
mesh_terms: D000363:Agaricales / Q000201:enzymology*; D000595:Amino Acid Sequence; D000818:Animals; D055162:Biocatalysis; D050260:Carbohydrate Metabolism; D004563:Electrochemistry; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism*; D045542:PQQ Cofactor / Q000378:metabolism*; D017434:Protein Structure, Tertiary
chemical_list: D045542:PQQ Cofactor; D010088:Oxidoreductases