Fold: DNA/RNA-binding 3-helical bundle

core: 3-helices; bundle, closed or partly opened, right-handed twist; up-and down

Lineage:

1. Root: scop
2. Class: All alpha proteins
3. Fold: DNA/RNA-binding 3-helical bundle
   core: 3-helices; bundle, closed or partly opened, right-handed twist; up-and down

Superfamilies:

1. Homeodomain-like (9)
   consists only of helices
2. Methylated DNA-protein cysteine methyltransferase, C-terminal domain (1)
3. ARID-like domain (2)
   contains extra helices at both N- and C-termini
4. TnsA endonuclease, C-terminal domain (1)
   contains extra structures at both N- and C-termini
5. "Winged helix" DNA-binding domain (26)
   contains a small beta-sheet (wing)
6. C-terminal, effector domain of the bipartite response regulators (3)
   binds to DNA and RNA polymerase; the N-terminal, receiver domain belongs to the CheY family
7. Ribosomal protein L11, C-terminal domain (1)
8. Ribosomal protein S18 (1)
9. Polynucleotide phosporylase/guanosine pentaphospate synthase (PNPase/GPSI), domain 3 (1)
10. N-terminal Zn binding domain of HIV integrase (1)
11. RNA polymerase subunit RPB10 (1)