Fold: TIM beta/alpha-barrel

contains parallel beta-sheet barrel, closed; n=8, S=8; strand order 12345678
the first six superfamilies have similar phosphate-binding sites

Lineage:

1. Root: scop
2. Class: Alpha and beta proteins (a/b)
   Mainly parallel beta sheets (beta-alpha-beta units)
3. Fold: TIM beta/alpha-barrel
   contains parallel beta-sheet barrel, closed; n=8, S=8; strand order 12345678
   the first six superfamilies have similar phosphate-binding sites

Superfamilies:

1. Triosephosphate isomerase (TIM) (1)
2. Ribulose-phoshate binding barrel (4)
3. Thiamin phosphate synthase (1)
4. FMN-linked oxidoreductases (1)
5. Inosine monophosphate dehydrogenase (IMPDH) (1)
   The phosphape moiety of substrate binds in the 'common' phosphate-binding site
6. PLP-binding barrel (2)
   circular permutation of the canonical fold: begins with an alpha helix and ends with a beta-strand
7. NAD(P)-linked oxidoreductase (1)
8. (Trans)glycosidases (7)
9. Metallo-dependent hydrolases (3)
   the beta-sheet barrel is similarly distorted and capped by a C-terminal helix
   has transition metal ions bound inside the barrel
10. Aldolase (4)
    Common fold covers whole protein structure
11. Enolase C-terminal domain-like (2)
    binds metal ion (magnesium or manganese) in conserved site inside barrel
    N-terminal alpha+beta domain is common to this family
12. Phosphoenolpyruvate/pyruvate domain (6)
13. Malate synthase G (1)
14. RuBisCo, C-terminal domain (1)
15. Xylose isomerase-like (3)
    different families share similar but non-identical metal-binding sites
16. Bacterial luciferase-like (3)
    consists of clearly related families of somewhat different folds
17. Quinolinic acid phosphoribosyltransferase, C-terminal domain (1)
    imcomplete beta/alpha barrel with parallel beta-sheet of 7 strands
18. Phosphatidylinositol-specific phospholipase C (PI-PLC) (2)
19. Cobalamin (vitamin B12)-dependent enzymes (3)
20. tRNA-guanine transglycosylase (1)
21. Dihydropteroate synthetase-like (2)
22. Uroporphyrinogen decarboxylase, UROD (1)
23. Methylenetetrahydrofolate reductase (1)