Distinct regions of the Escherichia coli ParC C-terminal domain are required for substrate discrimination by topoisomerase IV.

ABSTRACT: Type IIA DNA topoisomerases are essential enzymes that use ATP to maintain chromosome supercoiling and remove links between sister chromosomes. In Escherichia coli, the type IIA topoisomerase topo IV rapidly removes positive supercoils and catenanes from DNA but is significantly slower when confronted with negatively supercoiled substrates. The ability of topo IV to discriminate between positively and negatively supercoiled DNA requires the C-terminal domain (CTD) of one of its two subunits, ParC. To determine how the ParC CTD might assist with substrate discrimination, we identified potential DNA interacting residues on the surface of the CTD, mutated these residues, and tested their effect on both topo IV enzymatic activity and DNA binding by the isolated domain. Surprisingly, different

SUBMITTER: Vos SM 

PROVIDER: S-EPMC3864023 | biostudies-literature | 2013 Sep

REPOSITORIES: biostudies-literature