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1k4s
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| - | [[Image:1k4s.gif|left|200px]]<br /><applet load="1k4s" size="350" color="white" frame="true" align="right" spinBox="true" | ||
| - | caption="1k4s, resolution 3.20Å" /> | ||
| - | '''HUMAN DNA TOPOISOMERASE I IN COVALENT COMPLEX WITH A 22 BASE PAIR DNA DUPLEX'''<br /> | ||
| - | == | + | ==HUMAN DNA TOPOISOMERASE I IN COVALENT COMPLEX WITH A 22 BASE PAIR DNA DUPLEX== |
| + | <StructureSection load='1k4s' size='340' side='right'caption='[[1k4s]], [[Resolution|resolution]] 3.20Å' scene=''> | ||
| + | == Structural highlights == | ||
| + | <table><tr><td colspan='2'>[[1k4s]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1K4S OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1K4S 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]] 3.2Å</td></tr> | ||
| + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=5IU:5-IODO-2-DEOXYURIDINE-5-MONOPHOSPHATE'>5IU</scene>, <scene name='pdbligand=PTR:O-PHOSPHOTYROSINE'>PTR</scene>, <scene name='pdbligand=SPT:5-THIO-THYMIDINE+PHOSPHONIC+ACID'>SPT</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=1k4s FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1k4s OCA], [https://pdbe.org/1k4s PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1k4s RCSB], [https://www.ebi.ac.uk/pdbsum/1k4s PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1k4s ProSAT]</span></td></tr> | ||
| + | </table> | ||
| + | == Disease == | ||
| + | [https://www.uniprot.org/uniprot/TOP1_HUMAN TOP1_HUMAN] Note=A chromosomal aberration involving TOP1 is found in a form of therapy-related myelodysplastic syndrome. Translocation t(11;20)(p15;q11) with NUP98. | ||
| + | == Function == | ||
| + | [https://www.uniprot.org/uniprot/TOP1_HUMAN TOP1_HUMAN] Releases the supercoiling and torsional tension of DNA introduced during the DNA replication and transcription by transiently cleaving and rejoining one strand of the DNA duplex. Introduces a single-strand break via transesterification at a target site in duplex DNA. The scissile phosphodiester is attacked by the catalytic tyrosine of the enzyme, resulting in the formation of a DNA-(3'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 5'-OH DNA strand. The free DNA strand then undergoes passage around the unbroken strand thus removing DNA supercoils. Finally, in the religation step, the DNA 5'-OH attacks the covalent intermediate to expel the active-site tyrosine and restore the DNA phosphodiester backbone (By similarity). Regulates the alternative splicing of tissue factor (F3) pre-mRNA in endothelial cells.<ref>PMID:2833744</ref> <ref>PMID:19168442</ref> <ref>PMID:14594810</ref> <ref>PMID:16033260</ref> | ||
| + | == 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/k4/1k4s_consurf.spt"</scriptWhenChecked> | ||
| + | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.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=1k4s ConSurf]. | ||
| + | <div style="clear:both"></div> | ||
| + | <div style="background-color:#fffaf0;"> | ||
| + | == Publication Abstract from PubMed == | ||
We report the x-ray crystal structure of human topoisomerase I covalently joined to double-stranded DNA and bound to the clinically approved anticancer agent Topotecan. Topotecan mimics a DNA base pair and binds at the site of DNA cleavage by intercalating between the upstream (-1) and downstream (+1) base pairs. Intercalation displaces the downstream DNA, thus preventing religation of the cleaved strand. By specifically binding to the enzyme-substrate complex, Topotecan acts as an uncompetitive inhibitor. The structure can explain several of the known structure-activity relationships of the camptothecin family of anticancer drugs and suggests that there are at least two classes of mutations that can produce a drug-resistant enzyme. The first class includes changes to residues that contribute to direct interactions with the drug, whereas a second class would alter interactions with the DNA and thereby destabilize the drug-binding site. | We report the x-ray crystal structure of human topoisomerase I covalently joined to double-stranded DNA and bound to the clinically approved anticancer agent Topotecan. Topotecan mimics a DNA base pair and binds at the site of DNA cleavage by intercalating between the upstream (-1) and downstream (+1) base pairs. Intercalation displaces the downstream DNA, thus preventing religation of the cleaved strand. By specifically binding to the enzyme-substrate complex, Topotecan acts as an uncompetitive inhibitor. The structure can explain several of the known structure-activity relationships of the camptothecin family of anticancer drugs and suggests that there are at least two classes of mutations that can produce a drug-resistant enzyme. The first class includes changes to residues that contribute to direct interactions with the drug, whereas a second class would alter interactions with the DNA and thereby destabilize the drug-binding site. | ||
| - | + | The mechanism of topoisomerase I poisoning by a camptothecin analog.,Staker BL, Hjerrild K, Feese MD, Behnke CA, Burgin AB Jr, Stewart L Proc Natl Acad Sci U S A. 2002 Nov 26;99(24):15387-92. Epub 2002 Nov 8. PMID:12426403<ref>PMID:12426403</ref> | |
| - | + | ||
| - | + | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |
| - | + | </div> | |
| + | <div class="pdbe-citations 1k4s" style="background-color:#fffaf0;"></div> | ||
| - | == | + | ==See Also== |
| - | + | *[[Topoisomerase 3D structures|Topoisomerase 3D structures]] | |
| - | [ | + | == References == |
| + | <references/> | ||
| + | __TOC__ | ||
| + | </StructureSection> | ||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
| - | [[Category: | + | [[Category: Large Structures]] |
| - | [[Category: Behnke | + | [[Category: Behnke CA]] |
| - | [[Category: | + | [[Category: Burgin Jr AB]] |
| - | [[Category: | + | [[Category: Feese MD]] |
| - | [[Category: | + | [[Category: Hjerrild K]] |
| - | [[Category: Staker | + | [[Category: Staker BL]] |
| - | [[Category: Stewart | + | [[Category: Stewart LJ]] |
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Current revision
HUMAN DNA TOPOISOMERASE I IN COVALENT COMPLEX WITH A 22 BASE PAIR DNA DUPLEX
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