1zr6
From Proteopedia
The crystal structure of an Acremonium strictum glucooligosaccharide oxidase reveals a novel flavinylation
Structural highlights
FunctionGOOX_SARSR Catalyzes the selective oxidation of C1 hydroxyl moieties on mono- and disaccharides with concomitant reduction of molecular oxygen to hydrogen peroxide. This results in the formation of the corresponding lactones, which typically undergo spontaneous hydrolysis. Glucooligosaccharide oxidase is able to oxidize the monosaccharide D-glucose as well as the disaccharides maltose, cellobiose, and lactose. In addition, it shows high selectivity for cello- and maltooligosaccharides, indicating that glucooligosaccharide oxidase prefers oligosaccharides with a beta-D-glucosyl unit on the reducing end and additional sugar units linked by alpha- or beta-1,4 glucosidic bonds.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedGlucooligosaccharide oxidase from Acremonium strictum has been screened for potential applications in oligosaccharide acid production and alternative carbohydrate detection, because it catalyzes the oxidation of glucose, maltose, lactose, cellobiose and cello- and maltooligosaccharides. We report the crystal structures of the enzyme and of its complex with an inhibitor, 5-amino-5-deoxy- cellobiono-1,5-lactam at 1.55- and 1.98-A resolution, respectively. Unexpectedly, the protein structure demonstrates the first known double attachment flavinylation, 6-S-cysteinyl, 8alpha-N1-histidyl FAD. The FAD cofactor is cross-linked to the enzyme via the C(6) atom and the 8alpha-methyl group of the isoalloxazine ring with Cys(130) and His(70), respectively. This sugar oxidase possesses an open carbohydrate-binding groove, allowing the accommodation of higher oligosaccharides. The complex structure suggests that this enzyme may prefer a beta-d-glucosyl residue at the reducing end with the conserved Tyr(429) acting as a general base to abstract the OH(1) proton in concert with the H(1) hydride transfer to the flavin N(5). Finally, a detailed comparison illustrates the structural conservation as well as the divergence between this protein and its related flavoenzymes. Crystal structure of glucooligosaccharide oxidase from Acremonium strictum: a novel flavinylation of 6-S-cysteinyl, 8alpha-N1-histidyl FAD.,Huang CH, Lai WL, Lee MH, Chen CJ, Vasella A, Tsai YC, Liaw SH J Biol Chem. 2005 Nov 18;280(46):38831-8. Epub 2005 Sep 9. PMID:16154992[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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