Human mitochondrial topoisomerase I.
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Zhang H, Barcelo JM, Lee B, Kohlhagen G, Zimonjic DB, Popescu NC, Pommier Y
Human mitochondrial topoisomerase I.
Proc Natl Acad Sci U S A. 2001 Sep 11;98(19):10608-13. Epub 2001 Aug 28.
- PubMed ID
- 11526219 [ View in PubMed]
- Abstract
Tension generated in the circular mitochondrial genome during replication and transcription points to the need for mtDNA topoisomerase activity. Here we report a 601-aa polypeptide highly homologous to nuclear topoisomerase I. The N-terminal domain of this novel topoisomerase contains a mitochondrial localization sequence and lacks a nuclear localization signal. Therefore, we refer to this polypeptide as top1mt. The pattern of top1mt expression matches the requirement for high mitochondrial activity in specific tissues. top1mt is a type IB topoisomerase that requires divalent metal (Ca(2+) or Mg(2+)) and alkaline pH for optimum activity. The TOP1mt gene is highly homologous to the nuclear TOP1 gene and consists of 14 exons. It is localized on human chromosome 8q24.3.