A highly processive 5'-3' exoribonuclease; no evidence has been seen for endonuclease activity. Prefers 5'-phosphate or 5'-hydroxyl ends; 5'-triphosphate substrates are very poorly degraded, does not degrade circular RNA. Does not degrade pre-tRNA(Trp) suggesting it is inhibited by strong secondary structures. Also degrades ssNDA but not dsDNA. Binds 2 Zn(2+) ions per subunit. It is not clear if Zn(2+) or Mg(2+) is physiologically important. Inhibited by 1,10-phenanthroline. Optimum pH is 6-8. Optimum temperature is 95 degrees Celsius. Homodimer. Mutagenesis of His-410 to Val in the T.kodakaraensis homolog (AC Q5JH57) reduces exoribonuclease activity to 1%. Belongs to the metallo-beta-lactamase superfamily. RNA-metabolizing metallo-beta-lactamase-like family. Archaeal RNase J subfamily. Truncated N-terminus.