An RNase that has 5'-3' exonuclease and possible endonuclease activity. Involved in maturation of rRNA and in some organisms also mRNA maturation and/or decay (By similarity). Has both beta-lactamase and RNase activity, but the physiological relevance of the beta-lactamase activity, i.e. whether it confers antibiotic resistance, has not been shown (PubMed:21568871). a beta-lactam + H2O = a substituted beta-amino acid Binds up to 2 Zn(2+) ions per subunit. It is not clear if Zn(2+) or Mg(2+) is physiologically important. Both beta-lactamase and RNase activities are inhibited by chaperone DnaJ2. Homodimer, may be a subunit of the RNA degradosome (By similarity). Interacts with chaperone DnaJ2. Belongs to the metallo-beta-lactamase superfamily. RNA-metabolizing metallo-beta-lactamase-like family. Bacterial RNase J subfamily.