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1ej9

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Revision as of 23:33, 22 December 2014

CRYSTAL STRUCTURE OF HUMAN TOPOISOMERASE I DNA COMPLEX

Structural highlights

1ej9 is a 3 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Related:	1a36, 1a35, 1a31
Activity:	DNA topoisomerase, with EC number 5.99.1.2
Resources:	FirstGlance, OCA, RCSB, PDBsum

Disease

[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

[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.^[1] ^[2] ^[3] ^[4]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Human topoisomerase I helps to control the level of DNA supercoiling in cells and is vital for numerous DNA metabolic events, including replication, transcription, and recombination. The 2.6 A crystal structure of human topoisomerase I in noncovalent complex with a DNA duplex containing a cytosine at the -1 position of the scissile strand rather than the favored thymine is reported. The hydrogen bond between the O2 position of this -1 base and the epsilon-amino of the conserved Lys-532 residue, the only base-specific contact observed previously in the human topoisomerase I-DNA interaction, is maintained in this complex. Several unique features of this structure, however, have implications for the DNA-binding and active-site mechanisms of the enzyme. First, the ends of the DNA duplex were observed to shift by up to 5.4 A perpendicular to the DNA helical axis relative to structures reported previously, suggesting a novel degree of plasticity in the interaction between human topoisomerase I and its DNA substrate. Second, 12 additional residues at the NH(2) terminus of the protein (Trp-203-Gly-214) could be built in this structure, and they were found to pack against the putative hinge region implicated in the clamping of the enzyme around duplex DNA. Third, a water molecule was observed adjacent to the scissile phosphate and the active-site residues; the potential specific base character of this solvent molecule in the active-site mechanism of the enzyme is discussed. Fourth, the scissile phosphate group was found to be rotated by 75 degrees, bringing Lys-532 into hydrogen-bonding distance of one of the nonbridging phosphate oxygens. This orientation of the scissile phosphate group implicates Lys-532 as a fifth active-site residue, and also mimics the orientation observed for the 3'-phosphotyrosine linkage in the covalent human topoisomerase I-DNA complex structure. The implications of these structural features for the mechanism of the enzyme are discussed, including the potential requirement for a rotation of the scissile phosphate group during DNA strand cleavage and covalent attachment.

Novel insights into catalytic mechanism from a crystal structure of human topoisomerase I in complex with DNA.,Redinbo MR, Champoux JJ, Hol WG Biochemistry. 2000 Jun 13;39(23):6832-40. PMID:10841763^[5]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ D'Arpa P, Machlin PS, Ratrie H 3rd, Rothfield NF, Cleveland DW, Earnshaw WC. cDNA cloning of human DNA topoisomerase I: catalytic activity of a 67.7-kDa carboxyl-terminal fragment. Proc Natl Acad Sci U S A. 1988 Apr;85(8):2543-7. PMID:2833744
↑ Eisenreich A, Bogdanov VY, Zakrzewicz A, Pries A, Antoniak S, Poller W, Schultheiss HP, Rauch U. Cdc2-like kinases and DNA topoisomerase I regulate alternative splicing of tissue factor in human endothelial cells. Circ Res. 2009 Mar 13;104(5):589-99. doi: 10.1161/CIRCRESAHA.108.183905. Epub, 2009 Jan 22. PMID:19168442 doi:10.1161/CIRCRESAHA.108.183905
↑ Interthal H, Quigley PM, Hol WG, Champoux JJ. The role of lysine 532 in the catalytic mechanism of human topoisomerase I. J Biol Chem. 2004 Jan 23;279(4):2984-92. Epub 2003 Oct 31. PMID:14594810 doi:10.1074/jbc.M309959200
↑ Ioanoviciu A, Antony S, Pommier Y, Staker BL, Stewart L, Cushman M. Synthesis and mechanism of action studies of a series of norindenoisoquinoline topoisomerase I poisons reveal an inhibitor with a flipped orientation in the ternary DNA-enzyme-inhibitor complex as determined by X-ray crystallographic analysis. J Med Chem. 2005 Jul 28;48(15):4803-14. PMID:16033260 doi:10.1021/jm050076b
↑ Redinbo MR, Champoux JJ, Hol WG. Novel insights into catalytic mechanism from a crystal structure of human topoisomerase I in complex with DNA. Biochemistry. 2000 Jun 13;39(23):6832-40. PMID:10841763

1 Structural highlights
2 Disease
3 Function
4 Evolutionary Conservation
5 Publication Abstract from PubMed
6 See Also
7 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/1ej9"

@@ Line 3: / Line 3: @@
 == Structural highlights ==
 <table><tr><td colspan='2'>[[1ej9]] is a 3 chain structure with sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1EJ9 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1EJ9 FirstGlance]. <br>
-</td></tr><tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1a36|1a36]], [[1a35|1a35]], [[1a31|1a31]]</td></tr>
+</td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1a36|1a36]], [[1a35|1a35]], [[1a31|1a31]]</td></tr>
-<tr><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/DNA_topoisomerase DNA topoisomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.99.1.2 5.99.1.2] </span></td></tr>
+<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/DNA_topoisomerase DNA topoisomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.99.1.2 5.99.1.2] </span></td></tr>
-<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1ej9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ej9 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1ej9 RCSB], [http://www.ebi.ac.uk/pdbsum/1ej9 PDBsum]</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=1ej9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ej9 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1ej9 RCSB], [http://www.ebi.ac.uk/pdbsum/1ej9 PDBsum]</span></td></tr>
-<table>
+</table>
 == Disease ==
 [[http://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.
@@ Line 38: / Line 38: @@
 [[Category: DNA topoisomerase]]
 [[Category: Homo sapiens]]
-[[Category: Champoux, J J.]]
+[[Category: Champoux, J J]]
-[[Category: Hol, W G.]]
+[[Category: Hol, W G]]
-[[Category: Redinbo, M R.]]
+[[Category: Redinbo, M R]]
 [[Category: Human]]
 [[Category: Isomerase-dna complex]]
 [[Category: Protein-dna complex]]
 [[Category: Type i topoisomerase]]

1ej9

From Proteopedia

Revision as of 23:33, 22 December 2014

CRYSTAL STRUCTURE OF HUMAN TOPOISOMERASE I DNA COMPLEX

Structural highlights

Disease

Function

Evolutionary Conservation

Publication Abstract from PubMed

See Also

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

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