Toxic component of a type II toxin-antitoxin (TA) system. Acts as an RNase. Upon expression in M.smegmatis inhibits translation, growth and colony formation. All its toxic effects are neutralized by coexpression with cognate antitoxin VapB2. Binds 1 Mg(2+) ion per monomer; in the crystal structure only 1 toxin is bound to Mg(2+). Probably active as a homodimer, which binds to a VapB2 antitoxin homodimer, which then oligomerizes further to a hetero-octamer. When in complex with antitoxin VapB2 the toxin activity is inhibited; 1 VapB2 may suffice to inhibit toxin. Belongs to the PINc/VapC protein family.