Lineage for Superfamily f.21.3: Respiratory nitrate reductase 1 gamma chain

1. Root: SCOP 1.69

2. Class f: Membrane and cell surface proteins and peptides [56835] (47 folds)

3. Fold f.21: Heme-binding four-helical bundle [81344] (3 superfamilies) core: four transmembrane helices, up-and-down bundle, binds one or two heme groups in between the helices

4. Superfamily f.21.3: Respiratory nitrate reductase 1 gamma chain [103501] (1 family) possible link between the two other superfamilies: this subunit corresponds to the gamma subunit of a functionally related Formate dehydrogenase N complex but is structurally closer to the Fumarate reductase subunit FrdC