1qrd

<table><tr><td colspan='2'>[[1qrd]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Rattus_rattus Rattus rattus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QRD OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1QRD FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CBD:CIBACRON+BLUE'>CBD</scene>, <scene name='pdbligand=DQN:DUROQUINONE'>DQN</scene>, <scene name='pdbligand=FAD:FLAVIN-ADENINE+DINUCLEOTIDE'>FAD</scene></td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/NAD(P)H_dehydrogenase_(quinone) NAD(P)H dehydrogenase (quinone)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.6.5.2 1.6.5.2] </span></td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1qrd FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1qrd OCA], [http://pdbe.org/1qrd PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1qrd RCSB], [http://www.ebi.ac.uk/pdbsum/1qrd PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1qrd ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/NQO1_RAT NQO1_RAT]] The enzyme apparently serves as a quinone reductase in connection with conjugation reactions of hydroquinons involved in detoxification pathways as well as in biosynthetic processes such as the vitamin K-dependent gamma-carboxylation of glutamate residues in prothrombin synthesis.

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== Publication Abstract from PubMed ==

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.

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<ref>PMID:7568029</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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<div class="pdbe-citations 1qrd" style="background-color:#fffaf0;"></div>

*[[Quinone reductase|Quinone reductase]]

[[Category: Amzel, L M]]

[[Category: Bianchet, M A]]

[[Category: Li, R]]

[[Category: Talalay, P]]

[[Category: Oxidoreductase]]