_EC 3.1.13.- Exoribonucleases producing 5'-phosphomonoesters. 945 PDB entries  
EC 3.-.-.- Hydrolases. [21,435 PDB entries]
EC 3.1.-.- Acting on ester bonds. [6,048 PDB entries]
EC 3.1.13.- Exoribonucleases producing 5'-phosphomonoesters. [945 PDB entries]    
EC 3.1.13.1 Exoribonuclease Ii. [4 PDB entries]
EC 3.1.13.2 Exoribonuclease H. [915 PDB entries]
EC 3.1.13.3 Oligonucleotidase. [-]
EC 3.1.13.4 Poly(A)-specific ribonuclease. [25 PDB entries]
EC 3.1.13.5 Ribonuclease D. [1 PDB entries]

[-] signifies that there are no PDB entries for the given enzyme subclass