_EC 6.3.1.- Acid--ammonia (or amide) ligases (amide synthases). 70 PDB entries  
EC 6.-.-.- Ligases. [1,566 PDB entries]
EC 6.3.-.- Forming carbon-nitrogen bonds. [791 PDB entries]
EC 6.3.1.- Acid--ammonia (or amide) ligases (amide synthases). [70 PDB entries]    
EC 6.3.1.1 Aspartate--ammonia ligase. [3 PDB entries]
EC 6.3.1.2 Glutamate--ammonia ligase. [31 PDB entries]
EC 6.3.1.3 Transferred entry: 6.3.4.13. [-]
EC 6.3.1.4 Aspartate--ammonia ligase (ADP-forming). [-]
EC 6.3.1.5 NAD(+) synthase. [23 PDB entries]
EC 6.3.1.6 Glutamate--ethylamine ligase. [-]
EC 6.3.1.7 4-methyleneglutamate--ammonia ligase. [-]
EC 6.3.1.8 Glutathionylspermidine synthase. [9 PDB entries]
EC 6.3.1.9 Trypanothione synthase. [3 PDB entries]
EC 6.3.1.10 Adenosylcobinamide-phosphate synthase. [-]
EC 6.3.1.11 Glutamate--putrescine ligase. [-]
EC 6.3.1.12 D-aspartate ligase. [-]
EC 6.3.1.13 L-cysteine:1D-myo-inositol 2-amino-2-deoxy-alpha-D-glucopyranoside [1 PDB entries]
EC 6.3.1.14 Diphthine--ammonia ligase. [-]
EC 6.3.1.15 8-demethylnovobiocic acid synthase. [-]
EC 6.3.1.16 Transferred entry: 6.3.3.6. [-]
EC 6.3.1.17 Beta-citrylglutamate synthase. [-]

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