1QRD

QUINONE REDUCTASE/FAD/CIBACRON BLUE/DUROQUINONE COMPLEX

Summary for 1QRD

• Entry DOI: 10.2210/pdb1qrd/pdb
• Descriptor: QUINONE-REDUCTASE, FLAVIN-ADENINE DINUCLEOTIDE, CIBACRON BLUE, ... (5 entities in total)
• Functional Keywords: quinone-reductase (cytosolic), oxidoreductase, flavoprotein
• Biological source: Rattus rattus (black rat)
• Cellular location: Cytoplasm: P05982
• Total number of polymer chains: 2
• Total formula weight: 65152.57

Authors

Li, R.,Bianchet, M.A.,Talalay, P.,Amzel, L.M. (deposition date: 1995-07-28, release date: 1996-10-14, Last modification date: 2024-02-14)

Primary citation

Li, R.,Bianchet, M.A.,Talalay, P.,Amzel, L.M.
The three-dimensional structure of NAD(P)H:quinone reductase, a flavoprotein involved in cancer chemoprotection and chemotherapy: mechanism of the two-electron reduction.
Proc.Natl.Acad.Sci.USA, 92:8846-8850, 1995

PubMed Abstract: Quinone reductase [NAD(P)H:(quinone acceptor) oxidoreductase, EC 1.6.99.2], also called DT diaphorase, is a homodimeric FAD-containing enzyme that catalyzes obligatory NAD(P)H-dependent two-electron reductions of quinones and protects cells against the toxic and neoplastic effects of free radicals and reactive oxygen species arising from one-electron reductions. These two-electron reductions participate in the reductive bioactivation of cancer chemotherapeutic agents such as mitomycin C in tumor cells. Thus, surprisingly, the same enzymatic reaction that protects normal cells activates cytotoxic drugs used in cancer chemotherapy. The 2.1-A crystal structure of rat liver quinone reductase reveals that the folding of a portion of each monomer is similar to that of flavodoxin, a bacterial FMN-containing protein. Two additional portions of the polypeptide chains are involved in dimerization and in formation of the two identical catalytic sites to which both monomers contribute. The crystallographic structures of two FAD-containing enzyme complexes (one containing NADP+, the other containing duroquinone) suggest that direct hydride transfers from NAD(P)H to FAD and from FADH2 to the quinone [which occupies the site vacated by NAD(P)H] provide a simple rationale for the obligatory two-electron reductions involving a ping-pong mechanism.

PubMed: 7568029
DOI: 10.1073/pnas.92.19.8846

Experimental method

X-RAY DIFFRACTION (2.4 Å)