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Annotation rule MF_00953 |
General rule information
[?]
Accession |
MF_00953 |
Dates |
27-MAR-2013 (Created) 19-NOV-2019 (Last updated, Version 9) |
Propagated annotation
[?]
Identifier, protein and gene names
[?]
Protein name |
RecName:
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Full=DNA topoisomerase 3;
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EC 5.6.2.1;
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AltName:
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Full=DNA topoisomerase III;
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Function |
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. |
Catalytic activity |
Reaction=ATP-independent breakage of single-stranded DNA, followed by passage and rejoining.; EC=5.6.2.1; |
case <FTGroup:1>
Cofactor |
Mg(2+) Note: Binds two Mg(2+) per subunit. |
else case <FTGroup:2>
end case
Similarity |
Belongs to the type IA topoisomerase family. |
case <FTGroup:1> or <FTGroup:2>
end case
GO:0003917; Molecular function: DNA topoisomerase type I (single strand cut, ATP-independent) activity.
case <FTGroup:1> or <FTGroup:2>
GO:0000287; Molecular function: magnesium ion binding.
end case
GO:0006265; Biological process: DNA topological change.
From: TOP3_ECOLI (P14294) |
Key
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From
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To
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Description
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Tag
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Condition
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FTGroup
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REGION (Optional)
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194
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199
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Interaction with DNA
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[SN]-x-G-R-V-Q
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ACT_SITE
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328
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328
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O-(5'-phospho-DNA)-tyrosine intermediate
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Y
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case <OC:Proteobacteria>
METAL
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7
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7
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Magnesium 1; catalytic
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E
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1
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METAL
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103
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103
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Magnesium 1; catalytic
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D
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1
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METAL
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103
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103
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Magnesium 2
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D
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1
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METAL
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105
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105
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Magnesium 2
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D
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1
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else
METAL
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7
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7
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Magnesium; catalytic
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E
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2
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METAL
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103
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103
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Magnesium; catalytic
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D
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2
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end case
SITE (Optional)
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61
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61
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Interaction with DNA
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W
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SITE (Optional)
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170
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170
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Interaction with DNA
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W
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SITE (Optional)
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178
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178
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Interaction with DNA
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R
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SITE (Optional)
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185
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185
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Interaction with DNA
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R
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SITE (Optional)
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330
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330
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Interaction with DNA
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R
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Additional information
[?]
Size range |
610-765 amino acids |
Related rules |
None |
Fusion |
None |