1h6v: Difference between revisions

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-[[Image:1h6v.gif|left|200px]]<br /><applet load="1h6v" size="350" color="white" frame="true" align="right" spinBox="true"
-caption="1h6v, resolution 3.0&Aring;" />
-'''MAMMALIAN THIOREDOXIN REDUCTASE'''<br />
-==Overview==
+==Mammalian thioredoxin reductase==
-Thioredoxin reductases (TrxRs) from mammalian cells contain an essential, selenocysteine residue in the conserved C-terminal sequence, Gly-Cys-SeCys-Gly forming a selenenylsulfide in the oxidized enzyme., Reduction by NADPH generates a selenolthiol, which is the active site in, reduction of Trx. The three-dimensional structure of the SeCys498Cys, mutant of rat TrxR in complex with NADP(+) has been determined to 3.0-A, resolution by x-ray crystallography. The overall structure is similar to, that of glutathione reductase (GR), including conserved amino acid, residues binding the cofactors FAD and NADPH. Surprisingly, all residues, directly interacting with the substrate glutathione disulfide in GR are, conserved despite the failure of glutathione disulfide to act as a, substrate for TrxR. The 16-residue C-terminal tail, which is unique to, mammalian TrxR, folds in such a way that it can approach the active site, disulfide of the other subunit in the dimer. A model of the complex of, TrxR with Trx suggests that electron transfer from NADPH to the disulfide, of the substrate is possible without large conformational changes. The, C-terminal extension typical of mammalian TrxRs has two functions: (i) it, extends the electron transport chain from the catalytic disulfide to the, enzyme surface, where it can react with Trx, and (ii) it prevents the, enzyme from acting as a GR by blocking the redox-active disulfide. Our, results suggest that mammalian TrxR evolved from the GR scaffold rather, than from its prokaryotic counterpart. This evolutionary switch renders, cell growth dependent on selenium.
+<StructureSection load='1h6v' size='340' side='right'caption='[[1h6v]], [[Resolution|resolution]] 3.00&Aring;' scene=''>
+== Structural highlights ==
+<table><tr><td colspan='2'>[[1h6v]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1H6V OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1H6V FirstGlance]. <br>
+</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3&#8491;</td></tr>
+<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FAD:FLAVIN-ADENINE+DINUCLEOTIDE'>FAD</scene>, <scene name='pdbligand=NDP:NADPH+DIHYDRO-NICOTINAMIDE-ADENINE-DINUCLEOTIDE+PHOSPHATE'>NDP</scene></td></tr>
+<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1h6v FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1h6v OCA], [https://pdbe.org/1h6v PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1h6v RCSB], [https://www.ebi.ac.uk/pdbsum/1h6v PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1h6v ProSAT]</span></td></tr>
+</table>
+== Function ==
+[https://www.uniprot.org/uniprot/TRXR1_RAT TRXR1_RAT]
+== Evolutionary Conservation ==
+[[Image:Consurf_key_small.gif|200px|right]]
+Check<jmol>
+  <jmolCheckbox>
+    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/h6/1h6v_consurf.spt"</scriptWhenChecked>
+    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
+    <text>to colour the structure by Evolutionary Conservation</text>
+  </jmolCheckbox>
+</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1h6v ConSurf].
+<div style="clear:both"></div>
+<div style="background-color:#fffaf0;">
+== Publication Abstract from PubMed ==
+Thioredoxin reductases (TrxRs) from mammalian cells contain an essential selenocysteine residue in the conserved C-terminal sequence Gly-Cys-SeCys-Gly forming a selenenylsulfide in the oxidized enzyme. Reduction by NADPH generates a selenolthiol, which is the active site in reduction of Trx. The three-dimensional structure of the SeCys498Cys mutant of rat TrxR in complex with NADP(+) has been determined to 3.0-A resolution by x-ray crystallography. The overall structure is similar to that of glutathione reductase (GR), including conserved amino acid residues binding the cofactors FAD and NADPH. Surprisingly, all residues directly interacting with the substrate glutathione disulfide in GR are conserved despite the failure of glutathione disulfide to act as a substrate for TrxR. The 16-residue C-terminal tail, which is unique to mammalian TrxR, folds in such a way that it can approach the active site disulfide of the other subunit in the dimer. A model of the complex of TrxR with Trx suggests that electron transfer from NADPH to the disulfide of the substrate is possible without large conformational changes. The C-terminal extension typical of mammalian TrxRs has two functions: (i) it extends the electron transport chain from the catalytic disulfide to the enzyme surface, where it can react with Trx, and (ii) it prevents the enzyme from acting as a GR by blocking the redox-active disulfide. Our results suggest that mammalian TrxR evolved from the GR scaffold rather than from its prokaryotic counterpart. This evolutionary switch renders cell growth dependent on selenium.
-==About this Structure==
+Three-dimensional structure of a mammalian thioredoxin reductase: implications for mechanism and evolution of a selenocysteine-dependent enzyme.,Sandalova T, Zhong L, Lindqvist Y, Holmgren A, Schneider G Proc Natl Acad Sci U S A. 2001 Aug 14;98(17):9533-8. Epub 2001 Jul 31. PMID:11481439<ref>PMID:11481439</ref>
-H6V is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with <scene name='pdbligand=FAD:'>FAD</scene> and <scene name='pdbligand=NDP:'>NDP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Transferred_entry:_1.8.1.9 Transferred entry: 1.8.1.9], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.6.4.5 1.6.4.5] Known structural/functional Sites: <scene name='pdbsite=FAA:Fad+Binding+Site+For+Chain+A'>FAA</scene>, <scene name='pdbsite=FAB:Fad+Binding+Site+For+Chain+B'>FAB</scene>, <scene name='pdbsite=FAC:Fad+Binding+Site+For+Chain+C'>FAC</scene>, <scene name='pdbsite=FAD:Fad+Binding+Site+For+Chain+D'>FAD</scene>, <scene name='pdbsite=FAE:Fad+Binding+Site+For+Chain+E'>FAE</scene>, <scene name='pdbsite=FAF:Fad+Binding+Site+For+Chain+F'>FAF</scene>, <scene name='pdbsite=NDA:Ndp+Binding+Site+For+Chain+A'>NDA</scene>, <scene name='pdbsite=NDB:Ndp+Binding+Site+For+Chain+B'>NDB</scene>, <scene name='pdbsite=NDC:Ndp+Binding+Site+For+Chain+C'>NDC</scene>, <scene name='pdbsite=NDD:Ndp+Binding+Site+For+Chain+D'>NDD</scene>, <scene name='pdbsite=NDE:Ndp+Binding+Site+For+Chain+E'>NDE</scene> and <scene name='pdbsite=NDF:Ndp+Binding+Site+For+Chain+F'>NDF</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1H6V OCA].
-==Reference==
+From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
-Three-dimensional structure of a mammalian thioredoxin reductase: implications for mechanism and evolution of a selenocysteine-dependent enzyme., Sandalova T, Zhong L, Lindqvist Y, Holmgren A, Schneider G, Proc Natl Acad Sci U S A. 2001 Aug 14;98(17):9533-8. Epub 2001 Jul 31. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11481439 11481439]
+</div>
+<div class="pdbe-citations 1h6v" style="background-color:#fffaf0;"></div>
+==See Also==
+*[[Thioredoxin reductase 3D structures|Thioredoxin reductase 3D structures]]
+== References ==
+<references/>
+__TOC__
+</StructureSection>
+[[Category: Large Structures]]
 [[Category: Rattus norvegicus]]
-[[Category: Single protein]]
+[[Category: Holmgren A]]
-[[Category: Transferred entry: 1.8.1.9]]
+[[Category: Lindqvist Y]]
-[[Category: Holmgren, A.]]
+[[Category: Sandalova T]]
-[[Category: Lindqvist, Y.]]
+[[Category: Schneider G]]
-[[Category: Sandalova, T.]]
+[[Category: Zhong L]]
-[[Category: Schneider, G.]]
-[[Category: Zhong, L.]]
-[[Category: FAD]]
-[[Category: NDP]]
-[[Category: flavoprotein]]
-[[Category: pyridine nucleotide-disulfide oxidoreductase]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Feb  3 09:47:08 2008''