Volume 70, Issue 1 pp. 176-187
Research Article

Structures of dimeric dihydrodiol dehydrogenase apoenzyme and inhibitor complex: Probing the subunit interface with site-directed mutagenesis

Vincenzo Carbone

Vincenzo Carbone

Department of Medicinal Chemistry, Victorian College of Pharmacy, Monash University, Parkville, Victoria 3052, Australia

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Satoshi Endo

Satoshi Endo

Laboratory of Biochemistry, Gifu Pharmaceutical University, Gifu 502-8585, Japan

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Rie Sumii

Rie Sumii

Laboratory of Biochemistry, Gifu Pharmaceutical University, Gifu 502-8585, Japan

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Roland P.-T. Chung

Roland P.-T. Chung

Department of Medicinal Chemistry, Victorian College of Pharmacy, Monash University, Parkville, Victoria 3052, Australia

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Toshiyuki Matsunaga

Toshiyuki Matsunaga

Laboratory of Biochemistry, Gifu Pharmaceutical University, Gifu 502-8585, Japan

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Akira Hara

Akira Hara

Laboratory of Biochemistry, Gifu Pharmaceutical University, Gifu 502-8585, Japan

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Ossama El-Kabbani

Corresponding Author

Ossama El-Kabbani

Department of Medicinal Chemistry, Victorian College of Pharmacy, Monash University, Parkville, Victoria 3052, Australia

Department of Medicinal Chemistry, Victorian College of Pharmacy, Monash University, Parkville, Victoria 3052, Australia===Search for more papers by this author
First published: 24 July 2007
Citations: 9

Abstract

Dimeric dihydrodiol dehydrogenase (DD) catalyses the nicotinamide adenine dinucleotide phosphate (NADP+)-dependent oxidation of trans-dihydrodiols of aromatic hydrocarbons to their corresponding catechols. This is the first report of the crystal structure of the dimeric enzyme determined at 2.0 Å resolution. The tertiary structure is formed by a classical dinucleotide binding fold comprising of two βαβαβ motifs at the N-terminus and an eight-stranded, predominantly antiparallel β-sheet at the C-terminus. The active-site of DD, occupied either by a glycerol molecule or the inhibitor 4-hydroxyacetophenone, is located in the C-terminal domain of the protein and maintained by a number of residues including Lys97, Trp125, Phe154, Leu158, Val161, Asp176, Leu177, Tyr180, Trp254, Phe279, and Asp280. The dimer interface is stabilized by a large number of intermolecular contacts mediated by the β-sheet of each monomer, which includes an intricate hydrogen bonding network maintained in principal by Arg148 and Arg202. Site-directed mutagenesis has demonstrated that the intact dimer is not essential for catalytic activity. The similarity between the quaternary structures of mammalian DD and glucose-fructose oxidoreductase isolated from the prokaryotic organism Zymomonas mobilis suggests that both enzymes are members of a unique family of oligomeric proteins and may share a common ancestral gene. Proteins 2008. © 2007 Wiley-Liss, Inc.

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