Toxic component of a type II toxin-antitoxin (TA) system. Processes pre-16S-rRNA at its 3' end (the D-site) to yield the mature 3' end (By similarity). Binds 1 zinc ion per subunit. Has 2 structurally independent domains; the N-terminal PINc domain which binds Mn(2+), rRNA substrate and probably has endoribonuclease activity, and the C-terminal zinc ribbon domain which also binds rRNA substrate. Belongs to the PINc/VapC protein family.