An RNase that has endonuclease and 5'-3' exonuclease activity. The 5'-exonuclease activity acts on 5'-monophosphate but not 5'-triphosphate ends. Endonuclease activity can cleave within 4 nucleotides of the 5'-end of a triphosphorylated RNA. Plays the major role in pre-23S rRNA maturation, and a minor role in processing of pre-5S and pre-16S rRNA. Binds up to 2 Zn(2+) ions per subunit. It is not clear if Zn(2+) or Mg(2+) is physiologically important. Homodimer. Non-essential, it can be deleted. No effect on processing of furA-katG operon mRNA or of pre-5S rRNA processing. Complete loss of mature 23S rRNA. Minor effects on pre-16S rRNA processing. A double rnj-rne depletion mutant indicates this enzyme plays a role in degradation of previously processed pre-16S rRNAs and a decrease in mature 5S rRNA. Belongs to the metallo-beta-lactamase superfamily. RNA-metabolizing metallo-beta-lactamase-like family. Bacterial RNase J subfamily.