Mechanisms for defining supercoiling set point of DNA gyrase orthologs: I. A nonconserved acidic C-terminal tail modulates escherichia coli gyrase activity

Elsa M. Tretter, James M. Berger

Research output: Contribution to journalArticlepeer-review

Abstract

DNA topoisomerases manage chromosome supercoiling and organization in all cells. Gyrase, a prokaryotic type IIA topoisomerase, consumes ATP to introduce negative supercoils through a strand passage mechanism. All type IIA topoisomerases employ a similar set of catalytic domains for function; however, the activity and specificity of gyrase are augmented by a specialized DNA binding and wrapping element, termed the C-terminal domain (CTD), which is appended to its GyrA subunit. We have discovered that a nonconserved, acidic tail at the extreme C terminus of the Escherichia coli GyrA CTD has a dramatic and unexpected impact on gyrase function. Removal of the CTD tail enables GyrA to introduce writhe into DNA in the absence of GyrB, an activity exhibited by other GyrA orthologs, but not by wild-type E. coli GyrA. Strikingly, a "tail-less" gyrase holoenzyme is markedly impaired for DNA supercoiling capacity, but displays normal ATPase function. Our findings reveal that the E. coli GyrA tail regulates DNA wrapping by the CTD to increase the coupling efficiency between ATP turnover and supercoiling, demonstrating that CTD functions can be fine-tuned to control gyrase activity in a highly sophisticated manner.

Original languageEnglish (US)
Pages (from-to)18636-18644
Number of pages9
JournalJournal of Biological Chemistry
Volume287
Issue number22
DOIs
StatePublished - May 25 2012
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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