InterPro : IPR008336

Name  DNA topoisomerase I, DNA binding, eukaryotic-type Short Name  TopoI_DNA-bd_euk
Type  Domain 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 N-terminal DNA-binding domain found in eukaryotic topoisomerase I, which is a type IB enzymes. To cleave the DNA backbone, these enzymes must make a transient phosphotyrosine bond. The N-terminal domain of human topoisomerase I is thought to coordinate the restriction of free strand rotation during the topoisomerisation step of catalysis. A conserved tryptophan residue may be important for the DNA-interaction ability of the N-terminal domain []. Human topoisomerase I has been shown to be inhibited by camptothecin (CPT), a plant alkaloid with antitumour activity. 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 [].

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



1 Child Features

Id Name Short Name Type
IPR013030 DNA topoisomerase I, DNA binding, mixed alpha/beta motif, eukaryotic-type TopoI_DNA-bd_mixed-a/b_euk Domain

0 Contains

0 Found In

0 Parent Features

6 Publications

First Author Title Year Journal Volume Pages
Roca J The mechanisms of DNA topoisomerases. 1995 Trends Biochem Sci 20 156-60
Champoux JJ DNA topoisomerases: structure, function, and mechanism. 2001 Annu Rev Biochem 70 369-413
Gadelle D Phylogenomics of type II DNA topoisomerases. 2003 Bioessays 25 232-42
Wang JC Cellular roles of DNA topoisomerases: a molecular perspective. 2002 Nat Rev Mol Cell Biol 3 430-40
Redinbo MR Crystal structures of human topoisomerase I in covalent and noncovalent complexes with DNA. 1998 Science 279 1504-13
Frøhlich RF Regions within the N-terminal domain of human topoisomerase I exert important functions during strand rotation and DNA binding. 2004 J Mol Biol 336 93-103

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Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)