To improve security and privacy, we are moving our web pages and services from HTTP to HTTPS.
To give users of web services time to transition to HTTPS, we will support separate HTTP and HTTPS services until the end of 2017.
From January 2018 most HTTP traffic will be automatically redirected to HTTPS. [more...]
View this page in https
PROSITE documentation PDOC00159

Eukaryotic DNA topoisomerase I active site





Description

DNA topoisomerase I (EC 5.99.1.2) [1,2,3,4] is one of the two types of enzyme that catalyze the interconversion of topological DNA isomers. Type I topoisomerases act by catalyzing the transient breakage of DNA, one strand at a time, and the subsequent rejoining of the strands. When a eukaryotic type 1 topoisomerase breaks a DNA backbone bond, it simultaneously forms a protein-DNA link where the hydroxyl group of a tyrosine residue is joined to a 3'-phosphate on DNA, at one end of the enzyme-severed DNA strand. In eukaryotes and poxvirus topoisomerases I, there are a number of conserved residues in the region around the active site tyrosine.

Last update:

December 2001 / Text revised.

Technical section

PROSITE method (with tools and information) covered by this documentation:

TOPOISOMERASE_I_EUK, PS00176; Eukaryotic DNA topoisomerase I active site  (PATTERN)


References

1AuthorsSternglanz R.
TitleDNA topoisomerases.
SourceCurr. Opin. Cell Biol. 1:533-535(1989).
PubMed ID2560656

2AuthorsSharma A., Mondragon A.
TitleDNA topoisomerases.
SourceCurr. Opin. Struct. Biol. 5:39-47(1995).
PubMed ID7773745

3AuthorsLynn R.M., Bjornsti M.-A., Caron P.R., Wang J.C.
TitlePeptide sequencing and site-directed mutagenesis identify tyrosine-727 as the active site tyrosine of Saccharomyces cerevisiae DNA topoisomerase I.
SourceProc. Natl. Acad. Sci. U.S.A. 86:3559-3563(1989).
PubMed ID2542938

4AuthorsRoca J.
TitleThe mechanisms of DNA topoisomerases.
SourceTrends Biochem. Sci. 20:156-160(1995).
PubMed ID7770916



PROSITE is copyright. It is produced by the SIB Swiss Institute Bioinformatics. There are no restrictions on its use by non-profit institutions as long as its content is in no way modified. Usage by and for commercial entities requires a license agreement. For information about the licensing scheme send an email to
Prosite License or see: prosite_license.html.

Miscellaneous

View entry in original PROSITE document format
View entry in raw text format (no links)