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

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 wil

SUBMITTER: Tretter EM 

PROVIDER: S-EPMC3365713 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature