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1qrd

From Proteopedia

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[[Image:1qrd.gif|left|200px]]
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{{STRUCTURE_1qrd| PDB=1qrd | SCENE= }}
{{STRUCTURE_1qrd| PDB=1qrd | SCENE= }}
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'''QUINONE REDUCTASE/FAD/CIBACRON BLUE/DUROQUINONE COMPLEX'''
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===QUINONE REDUCTASE/FAD/CIBACRON BLUE/DUROQUINONE COMPLEX===
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==Overview==
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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.
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(as it appears on PubMed at http://www.pubmed.gov), where 7568029 is the PubMed ID number.
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{{ABSTRACT_PUBMED_7568029}}
==About this Structure==
==About this Structure==
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[[Category: Flavoprotein]]
[[Category: Flavoprotein]]
[[Category: Oxidoreductase]]
[[Category: Oxidoreductase]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 06:37:06 2008''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 09:00:43 2008''

Revision as of 06:00, 28 July 2008

Image:1qrd.png

Template:STRUCTURE 1qrd

QUINONE REDUCTASE/FAD/CIBACRON BLUE/DUROQUINONE COMPLEX

Template:ABSTRACT PUBMED 7568029

About this Structure

1QRD is a Single protein structure of sequence from Rattus rattus. Full crystallographic information is available from OCA.

Reference

The three-dimensional structure of NAD(P)H:quinone reductase, a flavoprotein involved in cancer chemoprotection and chemotherapy: mechanism of the two-electron reduction., Li R, Bianchet MA, Talalay P, Amzel LM, Proc Natl Acad Sci U S A. 1995 Sep 12;92(19):8846-50. PMID:7568029

Page seeded by OCA on Mon Jul 28 09:00:43 2008

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