Antitoxin component of a type II toxin-antitoxin (TA) system. Neutralizes the bacteriostatic effect of cognate toxin ParT by inserting into its active site. Forms heterotetrameric ParS(2)-ParT(2) complexes. The 2 antitoxin fragments do not make contact in the crystal structure. The C-terminus (residues 99-159) is sufficient to bind and neutralize toxin when expressed in E.coli. Belongs to the MbcA/ParS/Xre antitoxin family.