_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 Aspartate--ammonia ligase. [3 PDB entries]
EC Glutamate--ammonia ligase. [31 PDB entries]
EC Transferred entry: [-]
EC Aspartate--ammonia ligase (ADP-forming). [-]
EC NAD(+) synthase. [23 PDB entries]
EC Glutamate--ethylamine ligase. [-]
EC 4-methyleneglutamate--ammonia ligase. [-]
EC Glutathionylspermidine synthase. [9 PDB entries]
EC Trypanothione synthase. [3 PDB entries]
EC Adenosylcobinamide-phosphate synthase. [-]
EC Glutamate--putrescine ligase. [-]
EC D-aspartate ligase. [-]
EC L-cysteine:1D-myo-inositol 2-amino-2-deoxy-alpha-D-glucopyranoside [1 PDB entries]
EC Diphthine--ammonia ligase. [-]
EC 8-demethylnovobiocic acid synthase. [-]
EC Transferred entry: [-]
EC Beta-citrylglutamate synthase. [-]

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