Single strand-specific metallo-endoribonuclease involved in late-stage 70S ribosome quality control and in maturation of the 3' terminus of the 16S rRNA. Acts together with the RNase R to eliminate defective 70S ribosomes, but not properly matured 70S ribosomes or individual subunits, by a process mediated specifically by the 30S ribosomal subunit. Involved in the processing of 16S, 23S and 5S rRNAs, with a particularly strong effect on maturation at both the 5'- and 3'-ends of 16S rRNA as well as maturation of the 5'-end of 23S and 5S rRNAs. Binds 1 zinc ion. Inhibited by EDTA. By heat shock. Mutants show defects in 16S rRNA maturation, ribosome activity, translational fidelity, and ribosome assembly. They have severe growth defect at high temperatures, essentially no thermotolerance at lethal temperatures. They also show a decrease in polysomes and a large increase in both free 50S and free 30S ribosomal subunits relative to 70S ribosomes. Belongs to the endoribonuclease YbeY family.