Fold: The "swivelling" beta/beta/alpha domain

3 layers: b/b/a; the central sheet is parallel, and the other one is antiparallel; there are some variations in topology
this domain is thought to be mobile in all proteins known to contain it

Lineage:

1. Root: scop
2. Class: Alpha and beta proteins (a/b)
   Mainly parallel beta sheets (beta-alpha-beta units)
3. Fold: The "swivelling" beta/beta/alpha domain
   3 layers: b/b/a; the central sheet is parallel, and the other one is antiparallel; there are some variations in topology
   this domain is thought to be mobile in all proteins known to contain it

Superfamilies:

1. Phosphohistidine domain (2)
   contains barrel, closed, n=7, S=10
2. Aconitase, C-terminal domain (1)
   contains mixed beta-sheet barrel, closed n=7, S=10
3. Carbamoyl phosphate synthetase, small subunit N-terminal domain (1)
4. Transferrin receptor ectodomain, apical domain (1)
5. GroEL-like chaperone, apical domain (2)