_EC 6.3.1.- Acid--ammonia (or amine) ligases (amide synthases). 151 PDB entries  
EC 6.-.-.- Ligases. [3,414 PDB entries]
EC 6.3.-.- Forming carbon-nitrogen bonds. [1,455 PDB entries]
EC 6.3.1.- Acid--ammonia (or amine) ligases (amide synthases). [151 PDB entries]
EC 6.3.1.1 aspartate--ammonia ligase. [3 PDB entries]
EC 6.3.1.2 glutamine synthetase. [67 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. [30 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. [1 PDB entries]
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 [4 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. [-]
EC 6.3.1.18 gamma-glutamylanilide synthase. [-]
EC 6.3.1.19 prokaryotic ubiquitin-like protein ligase. [2 PDB entries]
EC 6.3.1.20 lipoate--protein ligase. [23 PDB entries]
EC 6.3.1.21 phosphoribosylglycinamide formyltransferase 2. [9 PDB entries]
EC 6.3.1.22 tRNAmet cytidine acetate ligase. [-]

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