Superfamily: 5' to 3' exonuclease, C-terminal subdomain

Lineage:

1. Root: scop
2. Class: All alpha proteins
3. Fold: SAM domain-like
   4-5 helices; bundle of two orthogonally packed alpha-hairpins; involved in the interactions with DNA and proteins
4. Superfamily: 5' to 3' exonuclease, C-terminal subdomain

Families:

1. 5' to 3' exonuclease, C-terminal subdomain (5)
   1. T4 RNase H
      1. Bacteriophage T4 (1)
   2. 5' to 3' exonuclease domain of DNA polymerase Taq
      1. Thermus aquaticus (4)
   3. T5 5'-exonuclease
      1. Bacteriophage T5 (2)
   4. Flap endonuclease-1
      1. Methanococcus jannaschii (2)
   5. Fen-1 nuclease
      1. Pyrococcus furiosus (1)