This system is the best understood of the plasmid partition system.
It is composed of an actin-like ATPAse, ParM, and a CBP called ParR. The centromere like site, parC contains two sets of five 11 base pair direct repeats separated by the parMR promoter.
The amino-acid sequence identity can go down to 15% between ParM and other actin-like ATPase.
The mechanism of partition involved here is a pushing mechanism:
# ParR binds to parC and pairs plasmids which form a nucleoprotein complex, or partition complex
# The partition complex serves as nucleation point for the polymerization of ParM; ParM-ATP complex inserts at this point and push plasmids apart
# The insertion leads to hydrolysis of ParM-ATP complex, leading to depolymerization of the filament
# At cell division, plasmids copies are at each cell extremity, and will end up in future daughter cell
The filament of ParM is regulated by the polymerization allowed by the presence the partition complex (ParR-parC), and by the depolymerization controlled by the ATPase activity of ParM.