Fold: P-loop containing nucleotide triphosphate hydrolases

3 layers: a/b/a, parallel or mixed beta-sheets of variable sizes

Lineage:

1. Root: scop
2. Class: Alpha and beta proteins (a/b)
   Mainly parallel beta sheets (beta-alpha-beta units)
3. Fold: P-loop containing nucleotide triphosphate hydrolases
   3 layers: a/b/a, parallel or mixed beta-sheets of variable sizes

Superfamilies:

1. P-loop containing nucleotide triphosphate hydrolases (14)
   division into families based on beta-sheet topologies
   1. Nucleotide and nucleoside kinases (16)
      parallel beta-sheet of 5 strands, order 23145
   2. Shikimate kinase (1)
      similar to the nucleotide/nucleoside kinases but acts on different substrate
   3. Chloramphenicol phosphotransferase (1)
      similar to the nucleotide/nucleoside kinases but acts on different substrate
   4. Adenosine-5'phosphosulfate kinase (APS kinase) (1)
   5. PAPS sulfotransferase (4)
      similar to the nucleotide/nucleoside kinases but transfer sulphate group
   6. Phosphoribulokinase/pantothenate kinase (2)
   7. 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase, kinase domain (1)
   8. G proteins (28)
      core: mixed beta-sheet of 6 strands, order 231456; strand 2 is antiparallel to the rest
   9. Motor proteins (7)
   10. Nitrogenase iron protein-like (10)
       core: parallel beta-sheet of 7 strands; order 3241567
   11. RecA protein-like (ATPase-domain) (9)
       core: mixed beta-sheet of 8 strands, order 32451678; strand 7 is antiparallel to the rest
   12. ABC transporter ATPase domain-like (7)
       there are two additional subdomains inserted into the central core that has a RecA-like topology
   13. Extended AAA-ATPase domain (13)
       fold is similar to that of RecA, but lacks the last two strands, followed by a family-specific all-alpha Arg-finger domain
   14. RNA helicase (1)
       duplication: consists of two similar domains, one binds NTP and the other binds RNA; also contains an all-alpha subdomain in the C-terminal extension