EC 5.6.2.1: DNA topoisomerase
Reaction catalysed:
ATP-independent breakage of single-stranded DNA, followed by passage and rejoining
Systematic name:
DNA topoisomerase
Alternative Name(s):
- DNA topoisomerase I
- Nicking-closing enzyme
- Omega-protein
- Relaxing enzyme
- Swivelase
- Type I DNA topoisomerase
- Untwisting enzyme
GO terms
Biochemical function:
Biological process:
Cellular component:
Sequence families
Protein families (Pfam)
InterPro annotations
IPR014727
Domain description:
DNA topoisomerase I, catalytic core, alpha/beta subdomain
Occurring in:
Occurring in:
IPR014711
Domain description:
DNA topoisomerase I, catalytic core, alpha-helical subdomain, eukaryotic-type
Occurring in:
Occurring in:
Structure domains
CATH domains
2.170.11.10
Class:
Mainly Beta
Architecture:
Beta Complex
Topology:
DNA Topoisomerase I; domain 2
Homology:
DNA Topoisomerase I, domain 2
Occurring in:
![The deposited structure of PDB entry <span class='highlight'>1t8i</span> contains 1 copy of CATH domain <span class='highlight'>2.170.11.10 (DNA Topoisomerase I; domain 2)</span> in <span class='highlight'>DNA topoisomerase 1</span>. Showing 1 copy in chain <span class='highlight'>D [auth A]</span>. The deposited structure of PDB entry 1t8i contains 1 copy of CATH domain 2.170.11.10 (DNA Topoisomerase I; domain 2) in DNA topoisomerase 1. Showing 1 copy in chain D [auth A].](https://www.ebi.ac.uk/pdbe/static/entry/1t8i_4_A_CATH_2.170.11.10_image-200x200.png)
1.10.132.10
Class:
Mainly Alpha
Architecture:
Orthogonal Bundle
Topology:
Topoisomerase I; Chain A, domain 4
Homology:
Topoisomerase I; Chain A, domain 4
Occurring in:
![The deposited structure of PDB entry <span class='highlight'>1t8i</span> contains 1 copy of CATH domain <span class='highlight'>1.10.132.10 (Topoisomerase I; Chain A, domain 4)</span> in <span class='highlight'>DNA topoisomerase 1</span>. Showing 1 copy in chain <span class='highlight'>D [auth A]</span>. The deposited structure of PDB entry 1t8i contains 1 copy of CATH domain 1.10.132.10 (Topoisomerase I; Chain A, domain 4) in DNA topoisomerase 1. Showing 1 copy in chain D [auth A].](https://www.ebi.ac.uk/pdbe/static/entry/1t8i_4_A_CATH_1.10.132.10_image-200x200.png)
3.90.15.10
Class:
Alpha Beta
Architecture:
Alpha-Beta Complex
Topology:
Topoisomerase I; Chain A, domain 3
Homology:
Topoisomerase I; Chain A, domain 3
Occurring in:
![The deposited structure of PDB entry <span class='highlight'>1t8i</span> contains 1 copy of CATH domain <span class='highlight'>3.90.15.10 (Topoisomerase I; Chain A, domain 3)</span> in <span class='highlight'>DNA topoisomerase 1</span>. Showing 1 copy in chain <span class='highlight'>D [auth A]</span>. The deposited structure of PDB entry 1t8i contains 1 copy of CATH domain 3.90.15.10 (Topoisomerase I; Chain A, domain 3) in DNA topoisomerase 1. Showing 1 copy in chain D [auth A].](https://www.ebi.ac.uk/pdbe/static/entry/1t8i_4_A_CATH_3.90.15.10_image-200x200.png)
SCOP annotations
56361
Class:
Alpha and beta proteins (a+b)
Fold:
DNA breaking-rejoining enzymes
Superfamily:
DNA breaking-rejoining enzymes
Occurring in:
![The deposited structure of PDB entry <span class='highlight'>1t8i</span> contains 1 copy of SCOP domain <span class='highlight'>56361 (Eukaryotic DNA topoisomerase I, catalytic core)</span> in <span class='highlight'>DNA topoisomerase 1</span>. Showing 1 copy in chain <span class='highlight'>D [auth A]</span>. The deposited structure of PDB entry 1t8i contains 1 copy of SCOP domain 56361 (Eukaryotic DNA topoisomerase I, catalytic core) in DNA topoisomerase 1. Showing 1 copy in chain D [auth A].](https://www.ebi.ac.uk/pdbe/static/entry/1t8i_4_A_SCOP_56361_image-200x200.png)
46597
Class:
All alpha proteins
Fold:
Long alpha-hairpin
Superfamily:
Eukaryotic DNA topoisomerase I, dispensable insert domain
Occurring in:
![The deposited structure of PDB entry <span class='highlight'>1t8i</span> contains 1 copy of SCOP domain <span class='highlight'>46597 (Eukaryotic DNA topoisomerase I, dispensable insert domain)</span> in <span class='highlight'>DNA topoisomerase 1</span>. Showing 1 copy in chain <span class='highlight'>D [auth A]</span>. The deposited structure of PDB entry 1t8i contains 1 copy of SCOP domain 46597 (Eukaryotic DNA topoisomerase I, dispensable insert domain) in DNA topoisomerase 1. Showing 1 copy in chain D [auth A].](https://www.ebi.ac.uk/pdbe/static/entry/1t8i_4_A_SCOP_46597_image-200x200.png)
56742
Class:
Multi-domain proteins (alpha and beta)
Fold:
Eukaryotic DNA topoisomerase I, N-terminal DNA-binding fragment
Superfamily:
Eukaryotic DNA topoisomerase I, N-terminal DNA-binding fragment
Occurring in:
![The deposited structure of PDB entry <span class='highlight'>1t8i</span> contains 1 copy of SCOP domain <span class='highlight'>56742 (Eukaryotic DNA topoisomerase I, N-terminal DNA-binding fragment)</span> in <span class='highlight'>DNA topoisomerase 1</span>. Showing 1 copy in chain <span class='highlight'>D [auth A]</span>. The deposited structure of PDB entry 1t8i contains 1 copy of SCOP domain 56742 (Eukaryotic DNA topoisomerase I, N-terminal DNA-binding fragment) in DNA topoisomerase 1. Showing 1 copy in chain D [auth A].](https://www.ebi.ac.uk/pdbe/static/entry/1t8i_4_A_SCOP_56742_image-200x200.png)