The Crystal Structure of the Catalytic Domain and the CytochromebDomain in a Eukaryotic PQQ-Dependent Dehydrogenase.Takeda, K., Ishida, T., Yoshida, M., Samejima, M., Ohno, H., Igarashi, K., Nakamura, N.
(2019) Appl.Environ.Microbiol. --: --
- PubMed: 31604769
- DOI: 10.1128/AEM.01692-19
- Primary Citation of Related Structures:
- PubMed Abstract:
Pyrroloquinoline quinone (PQQ) was discovered as a redox cofactor of prokaryotic glucose dehydrogenases in the 1960s, and subsequent studies have demonstrated its importance not only in bacterial systems but also in higher organisms. We have previous ...
Pyrroloquinoline quinone (PQQ) was discovered as a redox cofactor of prokaryotic glucose dehydrogenases in the 1960s, and subsequent studies have demonstrated its importance not only in bacterial systems but also in higher organisms. We have previously reported a novel eukaryotic quinohemoprotein that exhibited PQQ-dependent catalytic activity in a eukaryote. The enzyme, pyranose dehydrogenase, from the filamentous fungus Coprinopsis cinerea ( Cc PDH) of the Basidiomycete division, is composed of a catalytic PQQ-dependent domain classified as a member of the novel auxiliary activity family 12 (AA12), an AA8 cytochrome b domain, and a family 1 carbohydrate-binding module (CBM1), as defined by the Carbohydrate-Active enZymes (CAZy) database. Here, we present crystal structures of the AA12 domain in its apo and holo forms and the AA8 domain of this enzyme. The crystal structures of the holo-AA12 domain bound to PQQ provide direct evidence that eukaryotes have PQQ-dependent enzymes. The AA12 domain exhibits a six-bladed β-propeller fold that is also present in other known PQQ-dependent glucose dehydrogenases in bacteria. A loop structure around the active site and a calcium ion binding site are unique among the known structures of bacterial quinoproteins. The AA8 cytochrome domain has a positively charged area on its molecular surface, which is partly due to the propionate group of the heme interacting with Arg181; this feature differs from that of cytochrome b in the AA8 domain of the fungal cellobiose dehydrogenase and suggests that this difference may affect the pH dependence of electron transfer. Importance Pyrroloquinoline quinone (PQQ) is known as the "third coenzyme" following nicotinamide adenine dinucleotide (NAD + ) and flavin adenine dinucleotide (FAD). PQQ-dependent enzymes have been previously found only in prokaryotes, and the existence of a eukaryotic PQQ-dependent enzyme was in doubt. In 2014, we found an enzyme in mushrooms that catalyzes the oxidation of various sugars in a PQQ-dependent manner, which was a PQQ-dependent enzyme found in eukaryotes. This paper presents the X-ray crystal structures of this eukaryotic PQQ-dependent quinohemoprotein, which show the active site and identifies the amino acid residues involved in binding of the cofactor PQQ. The presented X-ray structures reveal that AA12 domain is in a binary complex with the coenzyme, clearly proving that PQQ-dependent enzymes exist in eukaryotes as well as prokaryotes. Because no biosynthetic system for PQQ has been reported in eukaryotes, future research on the symbiotic systems is expected.
Department of Environmental and Natural Resource Science, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.,JEM Utilization Center, Japan Aerospace Exploration Agency, Tsukuba, Ibaraki, 305-8505, Japan.,Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.,Department of Biomaterial Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan.,Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan firstname.lastname@example.org email@example.com.,Department of Biomaterial Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan firstname.lastname@example.org email@example.com.,VTT Technical Research Centre of Finland, P.O.Box 1000, Tietotie 2, Espoo FI-02044, Finland.