Practice question

In tripartite ParABS chromosome segregation ParA role dynamic scaffolding providing motive force. ParA proteins family Walker A ATPase dimerize upon ATP binding forming DNA binding competent form coating bacterial chromosome as cargo independent cloud. Upon ATP hydrolysis to ADP affinity for DNA drops, detachment occurs. ParB parS partition complex stimulates ATPase converting ParA ATP to ADP, so region behind moving complex depleted ParA, while front retains high concentration. Newly synthesized ParA ATP rebinds nucleoid generating gradient that directs chemophoretic movement of ParB parS origin complex toward higher ParA concentration toward cell pole. In some models ParA forms retracting filaments that pull chromosomes apart analogous to mitotic spindle. ParA responsible forming filaments that pull chromosomes apart, not binding origin directly which is ParB function, not breaking peptidoglycan nor attaching chromosomes to ribosomes. This ATP driven segregation ensures timely separation replicated oriC regions before septum closure, complemented by Topoisomerase IV decatenation and FtsK DNA translocase clearing trap at septum.