Lineage for Family a.25.4.2: PPE

1. Root: SCOP 1.73

2. Class a: All alpha proteins [46456] (258 folds)

3. Fold a.25: Ferritin-like [47239] (4 superfamilies) core: 4 helices; bundle, closed, left-handed twist; 1 crossover connection

4. Superfamily a.25.4: PE/PPE dimer-like [140459] (2 families) (hetero)dimer of alpha-hairpin subunits similar to that of the half-ferritin family; no bound metals inside the bundle

5. Family a.25.4.2: PPE [140463] (1 protein) Pfam PF00823; contains extra C-terminal alpha-hairpin, unlike the PE family subunit