4h7u

Crystal structure of pyranose dehydrogenase from Agaricus meleagris, wildtype

spinqualitylabelsall models 4h7u, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4h7u is a 1 chain structure with sequence from Leucoagaricus meleagris. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.6Å Ligands: FED, NAG, PO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PDH1_LEUMG Catalyzes the single-oxidation or sequential double oxidation reaction of carbohydrates primarily at carbon-2 and/or carbon-3 with the concomitant reduction of the flavin. The enzyme exhibits a broad sugar substrate specificity, oxidizing different aldopyranoses to the corresponding C-1, C-2, C-3 or C-1,2, C-2,3 and C-3,4 (di)dehydro sugars with substrate-specific regioselectivity. Accepts only a narrow range of electron acceptors such as substituted benzoquinones and complexed metal ions and reacts extremely slowly with O(2) as acceptor. May play a role in the natural recycling of plant matter by oxidizing all major monosaccharides in lignocellulose and by reducing quinone compounds or reactive radical species generated during lignin depolymerization. Publication Abstract from PubMed Pyranose dehydrogenases (PDHs) are extracellular flavin-dependent oxidoreductases secreted by litter-decomposing fungi with a role in natural recycling of plant matter. All major monosaccharides in lignocellulose are oxidized by PDH at comparable yields and efficiencies. Oxidation takes place as single-oxidation or sequential double-oxidation reactions of the carbohydrates, resulting in sugar derivatives oxidized primarily at C2, C3 or C2/3 with the concomitant reduction of the flavin. A suitable electron acceptor then reoxidizes the reduced flavin. Whereas oxygen is a poor electron acceptor for PDH, several alternative acceptors, e.g., quinone compounds, naturally present during lignocellulose degradation, can be used. We have determined the 1.6-A crystal structure of PDH from Agaricus meleagris. Interestingly, the flavin ring in PDH is modified by a covalent mono- or di-atomic species at the C(4a) position. Under normal conditions, PDH is not oxidized by oxygen; however, the related enzyme pyranose 2-oxidase (P2O) activates oxygen by a mechanism that proceeds via a covalent flavin C(4a)-hydroperoxide intermediate. Although the flavin C(4a) adduct is common in monooxygenases, it is unusual for flavoprotein oxidases, and it has been proposed that formation of the intermediate would be unfavorable in these oxidases. Thus, the flavin adduct in PDH not only shows that the adduct can be favorably accommodated in the active site, but also provides important details regarding the structural, spatial and physicochemical requirements for formation of this flavin intermediate in related oxidases. Extensive in silico modeling of carbohydrates in the PDH active site allowed us to rationalize the previously reported patterns of substrate specificity and regioselectivity. To evaluate the regioselectivity of D-glucose oxidation, reduction experiments were performed using fluorinated glucose. PDH was rapidly reduced by 3-fluorinated glucose, which has the C2 position accessible for oxidation, whereas 2-fluorinated glucose performed poorly (C3 accessible), indicating that the glucose C2 position is the primary site of attack. The 1.6 A crystal structure of pyranose dehydrogenase from Agaricus meleagris rationalizes substrate specificity and reveals a flavin intermediate.,Tan TC, Spadiut O, Wongnate T, Sucharitakul J, Krondorfer I, Sygmund C, Haltrich D, Chaiyen P, Peterbauer CK, Divne C PLoS One. 2013;8(1):e53567. doi: 10.1371/journal.pone.0053567. Epub 2013 Jan 9. PMID:23326459 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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