Antitoxin component of a type II toxin-antitoxin (TA) system. Upon expression in E.coli and in M.smegmatis counteracts the ribonuclease activity of cognate toxin MazF6. Forms a complex with cognate toxin MazF6 which neutralizes the toxin. Interacts physically with non-cognate toxins VapC27 and VapC40. Strongly induced (about 10-fold) by nitrosative stress.