Format

Send to

Choose Destination
Proc Natl Acad Sci U S A. 2001 May 22;98(11):6015-20. Epub 2001 May 15.

A type IB topoisomerase with DNA repair activities.

Author information

1
Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117871, Russia.

Abstract

Previously we have characterized type IB DNA topoisomerase V (topo V) in the hyperthermophile Methanopyrus kandleri. The enzyme has a powerful topoisomerase activity and is abundant in M. kandleri. Here we report two characterizations of topo V. First, we found that its N-terminal domain has sequence homology with both eukaryotic type IB topoisomerases and the integrase family of tyrosine recombinases. The C-terminal part of the sequence includes 12 repeats, each repeat consisting of two similar but distinct helix-hairpin-helix motifs; the same arrangement is seen in recombination protein RuvA and mammalian DNA polymerase beta. Second, on the basis of sequence homology between topo V and polymerase beta, we predict and demonstrate that topo V possesses apurinic/apyrimidinic (AP) site-processing activities that are important in base excision DNA repair: (i) it incises the phosphodiester backbone at the AP site, and (ii) at the AP endonuclease cleaved AP site, it removes the 5' 2-deoxyribose 5-phosphate moiety so that a single-nucleotide gap with a 3'-hydroxyl and 5'-phosphate can be filled by a DNA polymerase. Topo V is thus the prototype for a new subfamily of type IB topoisomerases and is the first example of a topoisomerase with associated DNA repair activities.

PMID:
11353838
PMCID:
PMC33414
DOI:
10.1073/pnas.111040498
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center