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Structure and Function of Caulobacter crescentus Aldose-aldose Oxidoreductase

DOI: 10.1042/BJ20150681 DOI Help
PMID: 26438878 PMID Help

Authors: H Taberman (University of Eastern Finland) , M. Andberg (University of Eastern Finland) , A. Koivula (University of Eastern Finland) , N. Hakulinen (University of Eastern Finland) , M. Penttila (VTT Technical Research Centre of Finland) , J. Rouvinen (University of Eastern Finland) , T. Parkkinen (University of Eastern Finland)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Biochemical Journal

State: Published (Approved)
Published: October 2015

Abstract: Aldose-aldose oxidoreductase ( Cc AAOR) is a recently characterized enzyme from the bacterial strain of Caulobacter crescentus CB15 belonging to the Gfo/Idh/MocA protein family. Cc AAOR catalyzes the oxidation and reduction of a panel of aldose monosaccharides using a tightly bound NADP(H) cofactor that is regenerated in the catalytic cycle. Furthermore, Cc AAOR can also oxidize 1,4-linked oligosaccharides. Here, we present novel crystal structures of the dimeric Cc AAOR in complex with the cofactor and glycerol, D-xylose, D-glucose, maltotriose, and D-sorbitol determined to 2.0, 1.8, 1.7, 1.9, and 1.8 Å resolutions, respectively. These complex structures allowed for a detailed analysis of the ligand-binding interactions. The structures showed that the C1 carbon of a substrate, which is either reduced or oxidized, is close to the reactive C4 carbon of the nicotinamide ring of NADP(H). In addition, the O1 hydroxyl group of the substrate, which is either protonated or deprotonated, is unexpectedly close to both Lys-104 and Tyr-189, which may both act as a proton donor or acceptor. This led us to hypothesize that this intriguing feature could be beneficial for Cc AAOR to catalyze the reduction of a linear form of a monosaccharide substrate and the oxidation of a pyranose form of the same substrate in a reaction cycle, during which the bound cofactor is regenerated.

Journal Keywords: Oxidoreductase; Nadp(H) Cofactor; Carbohydrate; Gfo/Idh/Moca Family

Subject Areas: Biology and Bio-materials

Instruments: I03-Macromolecular Crystallography

Other Facilities: ESRF

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