The accurate segregation of DNA is essential for the faithful inheritance of genetic information. Segregation of the prototypical P1 plasmid par system requires two proteins, ParA and ParB, and a centromere. When bound to ATP, ParA mediates segregation by interacting with centromere-bound ParB, but when bound to ADP, ParA fulfills a different function: DNA-binding transcription autoregulation. ParA consists of an elongated N-terminal alpha-helix which mediates dimerization, a winged-HTH and a Walker-box containing C-domain. This entry describes the N-terminal alpha helix domain combined with the winged HTH region [1].

1: Structural basis for ADP-mediated transcriptional regulation by P1 and P7 ParA. Dunham TD, Xu W, Funnell BE, Schumacher MA; EMBO J. 2009;28:1792-1802. PMID:19461582