1A80

Native 2,5-DIKETO-D-GLUCONIC acid reductase a from CORYNBACTERIUM SP. complexed with nadph

Summary for 1A80

• Entry DOI: 10.2210/pdb1a80/pdb
• Descriptor: 2,5-DIKETO-D-GLUCONIC ACID REDUCTASE A, NADPH DIHYDRO-NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE (3 entities in total)
• Functional Keywords: oxidoreductase, alpha8/beta8 barrel, 2, 5-diketo-d-gluconic acid, commercial vitamin c synthesis
• Biological source: Corynebacterium sp.
• Cellular location: Cytoplasm: P06632
• Total number of polymer chains: 1
• Total formula weight: 30765.89

Authors

Khurana, S.,Powers, D.B.,Anderson, S.,Blaber, M. (deposition date: 1998-03-31, release date: 1999-03-30, Last modification date: 2023-08-02)

Primary citation

Khurana, S.,Powers, D.B.,Anderson, S.,Blaber, M.
Crystal structure of 2,5-diketo-D-gluconic acid reductase A complexed with NADPH at 2.1-A resolution.
Proc.Natl.Acad.Sci.USA, 95:6768-6773, 1998

PubMed Abstract: The three-dimensional structure of Corynebacterium 2, 5-diketo-D-gluconic acid reductase A (2,5-DKGR A; EC 1.1.1.-), in complex with cofactor NADPH, has been solved by using x-ray crystallographic data to 2.1-A resolution. This enzyme catalyzes stereospecific reduction of 2,5-diketo-D-gluconate (2,5-DKG) to 2-keto-L-gulonate. Thus the three-dimensional structure has now been solved for a prokaryotic example of the aldo-keto reductase superfamily. The details of the binding of the NADPH cofactor help to explain why 2,5-DKGR exhibits lower binding affinity for cofactor than the related human aldose reductase does. Furthermore, changes in the local loop structure near the cofactor suggest that 2,5-DKGR will not exhibit the biphasic cofactor binding characteristics observed in aldose reductase. Although the crystal structure does not include substrate, the two ordered water molecules present within the substrate-binding pocket are postulated to provide positional landmarks for the substrate 5-keto and 4-hydroxyl groups. The structural basis for several previously described active-site mutants of 2,5-DKGR A is also proposed. Recent research efforts have described a novel approach to the synthesis of L-ascorbate (vitamin C) by using a genetically engineered microorganism that is capable of synthesizing 2,5-DKG from glucose and subsequently is transformed with the gene for 2,5-DKGR. These modifications create a microorganism capable of direct production of 2-keto-L-gulonate from D-glucose, and the gulonate can subsequently be converted into vitamin C. In economic terms, vitamin C is the single most important specialty chemical manufactured in the world. Understanding the structural determinants of specificity, catalysis, and stability for 2,5-DKGR A is of substantial commercial interest.

PubMed: 9618487
DOI: 10.1073/pnas.95.12.6768

Experimental method

X-RAY DIFFRACTION (2.1 Å)