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1ecl

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Revision as of 12:27, 25 December 2014

AMINO TERMINAL 67KDA DOMAIN OF ESCHERICHIA COLI DNA TOPOISOMERASE I (RESIDUES 2-590 OF MATURE PROTEIN) CLONING ARTIFACT ADDS TWO RESIDUES TO THE AMINO-TERMINUS WHICH WERE NOT OBSERVED IN THE EXPERIMENTAL ELECTRON DENSITY (GLY-2, SER-1).

Structural highlights

1ecl is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Gene:	TOPA (Escherichia coli)
Activity:	DNA topoisomerase, with EC number 5.99.1.2
Resources:	FirstGlance, OCA, RCSB, PDBsum

Function

[TOP1_ECOLI] Releases the supercoiling and torsional tension of DNA, which is 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-(5'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 3'-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 3'-OH attacks the covalent intermediate to expel the active-site tyrosine and restore the DNA phosphodiester backbone.^[1] ^[2] ^[3]

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

The three-dimensional structure of the 67K amino-terminal fragment of Escherichia coli DNA topoisomerase I has been determined to 2.2 A resolution. The polypeptide folds in an unusual way to give four distinct domains enclosing a hole large enough to accommodate a double-stranded DNA. The active-site tyrosyl residue, which is involved in the transient breakage of a DNA strand and the formation of a covalent enzyme-DNA intermediate, is present at the interface of two domains. The structure suggests a plausible mechanism by which E. coli DNA topoisomerase I and other members of the same DNA topoisomerase subfamily could catalyse the passage of one DNA strand through a transient break in another strand.

Three-dimensional structure of the 67K N-terminal fragment of E. coli DNA topoisomerase I.,Lima CD, Wang JC, Mondragon A Nature. 1994 Jan 13;367(6459):138-46. PMID:8114910^[4]

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

References

↑ Chen SJ, Wang JC. Identification of active site residues in Escherichia coli DNA topoisomerase I. J Biol Chem. 1998 Mar 13;273(11):6050-6. PMID:9497321
↑ Zhu CX, Tse-Dinh YC. The acidic triad conserved in type IA DNA topoisomerases is required for binding of Mg(II) and subsequent conformational change. J Biol Chem. 2000 Feb 25;275(8):5318-22. PMID:10681504
↑ Zhang Z, Cheng B, Tse-Dinh YC. Crystal structure of a covalent intermediate in DNA cleavage and rejoining by Escherichia coli DNA topoisomerase I. Proc Natl Acad Sci U S A. 2011 Apr 26;108(17):6939-44. Epub 2011 Apr 11. PMID:21482796 doi:http://dx.doi.org/10.1073/pnas.1100300108
↑ Lima CD, Wang JC, Mondragon A. Three-dimensional structure of the 67K N-terminal fragment of E. coli DNA topoisomerase I. Nature. 1994 Jan 13;367(6459):138-46. PMID:8114910 doi:http://dx.doi.org/10.1038/367138a0

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

Proteopedia Page Contributors and Editors (what is this?)

OCA

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

@@ Line 7: / Line 7: @@
 <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=1ecl FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ecl OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1ecl RCSB], [http://www.ebi.ac.uk/pdbsum/1ecl PDBsum]</span></td></tr>
 </table>
+== Function ==
+[[http://www.uniprot.org/uniprot/TOP1_ECOLI TOP1_ECOLI]] Releases the supercoiling and torsional tension of DNA, which is 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-(5'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 3'-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 3'-OH attacks the covalent intermediate to expel the active-site tyrosine and restore the DNA phosphodiester backbone.<ref>PMID:9497321</ref> <ref>PMID:10681504</ref> <ref>PMID:21482796</ref>
 == Evolutionary Conservation ==
 [[Image:Consurf_key_small.gif|200px|right]]

1ecl

From Proteopedia

Revision as of 12:27, 25 December 2014

AMINO TERMINAL 67KDA DOMAIN OF ESCHERICHIA COLI DNA TOPOISOMERASE I (RESIDUES 2-590 OF MATURE PROTEIN) CLONING ARTIFACT ADDS TWO RESIDUES TO THE AMINO-TERMINUS WHICH WERE NOT OBSERVED IN THE EXPERIMENTAL ELECTRON DENSITY (GLY-2, SER-1).

Structural highlights

Function

Evolutionary Conservation

Publication Abstract from PubMed

See Also

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

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