Protein Domain : IPR013499

Type:  Domain Name:  DNA topoisomerase I, eukaryotic-type
Description:  DNA topoisomerases regulate the number of topological links between two DNA strands (i.e. change the number of superhelical turns) by catalysing transient single- or double-strand breaks, crossing the strands through one another, then resealing the breaks []. These enzymes have several functions: to remove DNA supercoils during transcription and DNA replication; for strand breakage during recombination; for chromosome condensation; and to disentangle intertwined DNA during mitosis [, ]. DNA topoisomerases are divided into two classes: type I enzymes (; topoisomerases I, III and V) break single-strand DNA, and type II enzymes (; topoisomerases II, IV and VI) break double-strand DNA [].Type I topoisomerases are ATP-independent enzymes (except for reverse gyrase), and can be subdivided according to their structure and reaction mechanisms: type IA (bacterial and archaeal topoisomerase I, topoisomerase III and reverse gyrase) and type IB (eukaryotic topoisomerase I and topoisomerase V). These enzymes are primarily responsible for relaxing positively and/or negatively supercoiled DNA, except for reverse gyrase, which can introduce positive supercoils into DNA. This entry represents the C-terminal region of DNA topoisomerase I enzymes from eukaryotes (type IB enzymes). This region covers both the catalytic core and the DNA-binding domains.Human topoisomerase I has been shown to be inhibited by camptothecin (CPT), a plant alkaloid with antitumour activity []. The crystal structures of human topoisomerase I comprising the core and carboxyl-terminal domains in covalent and noncovalent complexes with 22-base pair DNA duplexes reveal an enzyme that "clamps" around essentially B-form DNA. The core domain and the first eight residues of the carboxyl-terminal domain of the enzyme, including the active-site nucleophile tyrosine-723, share significant structural similarity with the bacteriophage family of DNA integrases. A binding mode for the anticancer drug camptothecin has been proposed on the basis of chemical and biochemical information combined with the three-dimensional structures of topoisomerase I-DNA complexes []. Short Name:  TopoI_euk
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0 Child Features

5 Contains

DB identifier Type Name
IPR013500 Domain DNA topoisomerase I, catalytic core, eukaryotic-type
IPR014727 Domain DNA topoisomerase I, catalytic core, alpha/beta subdomain
IPR011010 Domain DNA breaking-rejoining enzyme, catalytic core
IPR014711 Domain DNA topoisomerase I, catalytic core, alpha-helical subdomain, eukaryotic-type
IPR018521 Active_site DNA topoisomerase I, active site

1 Cross References

Identifier
SM00435

0 Found In

4 GO Annotations

GO Term Gene Name
GO:0003677 IPR013499
GO:0003917 IPR013499
GO:0006265 IPR013499
GO:0005694 IPR013499

4 Ontology Annotations

GO Term Gene Name
GO:0003677 IPR013499
GO:0003917 IPR013499
GO:0006265 IPR013499
GO:0005694 IPR013499

0 Parent Features

3256 Proteins

DB identifier UniProt Accession Secondary Identifier Organism Name Length
109207 D8S5X0 PAC:15402587 Selaginella moellendorffii 597  
152781 D8S5V9 PAC:15422049 Selaginella moellendorffii 533  
145504 D8RB80 PAC:15421954 Selaginella moellendorffii 525  
evm.model.supercontig_12.228 PAC:16406779 Carica papaya 703  
27613.m000610 B9SSQ1 PAC:16798785 Ricinus communis 891  
Cucsa.042470.2 PAC:16952935 Cucumis sativus 872  
Cucsa.042470.1 A0A0A0L2W2 PAC:16952934 Cucumis sativus 889  
orange1.1g002904m PAC:18099999 Citrus sinensis 868  
orange1.1g002260m PAC:18099998 Citrus sinensis 946  
AT5G55300.1 P30181 PAC:19671117 Arabidopsis thaliana 916  
AT5G55300.2 F4K3F4 PAC:19671116 Arabidopsis thaliana 933  
AT5G55300.3 F4K3F5 PAC:19671118 Arabidopsis thaliana 564  
AT5G55310.1 Q9FJ79 PAC:19669161 Arabidopsis thaliana 917  
Thhalv10012622m V4LKD9 PAC:20206189 Eutrema salsugineum 904  
Thhalv10012620m V4LKD9 PAC:20206190 Eutrema salsugineum 904  
Thhalv10012607m V4LSR0 PAC:20205212 Eutrema salsugineum 920  
Ciclev10007461m V4UN92 PAC:20795588 Citrus clementina 824  
Ciclev10007398m V4UT45 PAC:20795586 Citrus clementina 902  
Ciclev10007400m V4UT45 PAC:20795587 Citrus clementina 902  
Lus10032571 PAC:23146365 Linum usitatissimum 869  
Lus10032572 PAC:23146336 Linum usitatissimum 376  
Lus10043175 PAC:23168391 Linum usitatissimum 963  
Lus10043172 PAC:23167928 Linum usitatissimum 694  
Potri.001G359700.2 A0A2K2C974 PAC:27043239 Populus trichocarpa 877  
Potri.001G359700.1 A0A2K2C974 PAC:27043240 Populus trichocarpa 877  
Potri.001G359700.3 PAC:27043241 Populus trichocarpa 799  
Potri.011G092700.2 PAC:27000687 Populus trichocarpa 783  
Potri.011G092700.4 A0A2K1YHS2 PAC:27000685 Populus trichocarpa 861  
Potri.011G092700.3 A0A2K1YHS2 PAC:27000686 Populus trichocarpa 861  
Potri.011G092700.1 A0A2K1YHS2 PAC:27000684 Populus trichocarpa 861  

6 Publications

First Author Title Year Journal Volume Pages PubMed ID
            7770916
            11395412
            12596227
            12042765
            1849260
            9488644