- Classes: Alpha and beta proteins (a+b)
 - Folds: Succinate dehydrogenase/fumarate reductase flavoprotein, catalytic domain
 - Superfamilies: Succinate dehydrogenase/fumarate reductase flavoprotein, catalytic domain
 - Families: Succinate dehydrogenase/fumarate reductase flavoprotein, catalytic domain
 
Protein Domains:
- Fumarate reductase
- [ABCD]
 - [A2B2C2]
 
 - Succinate dehydogenase
- [ABCD]
 - [ABCD]
 
 
	* [ ] : Polypeptide  - [AB] : Protein, [ab] : Small peptide
* ( ) : Nucleic acid - (AB) : DNA, (ab) : RNA
* ( ) : Nucleic acid - (AB) : DNA, (ab) : RNA
