Fold: Chelatase-like

duplication: tandem repeat of two domains; 3 layers (a/b/a); parallel beta-sheet of 4 strands, order 2134

Lineage:

1. Root: scop
2. Class: Alpha and beta proteins (a/b)
   Mainly parallel beta sheets (beta-alpha-beta units)
3. Fold: Chelatase-like
   duplication: tandem repeat of two domains; 3 layers (a/b/a); parallel beta-sheet of 4 strands, order 2134

Superfamilies:

1. Chelatase (2)
   interdomain linker is short; swapping of C-terminal helices between the two domains
2. "Helical backbone" metal receptor (3)
   contains a long alpha helical insertion in the interdomain linker