Fold: Heme-binding four-helical bundle

core: four transmembrane helices, up-and-down bundle, binds one or two heme groups in between the helices

Lineage:

1. Root: scop
2. Class: Membrane and cell surface proteins and peptides [56835]
   Does not include proteins in the immune system
3. Fold: Heme-binding four-helical bundle [81344]
   core: four transmembrane helices, up-and-down bundle, binds one or two heme groups in between the helices

Superfamilies:

1. Transmembrane di-heme cytochromes [81342] (2)
   Three of the four heme-ligands are conserved between the two families; both heme groups bind similarly but not identically
   uperfamily
   1. Cytochrome b of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase) [81642] (5)
      a part (domain) of a larger mitochondrial cytochrome b subunit, separate subunit in plants and cyanobacteria
      1. Mitochondrial cytochrome b subunit, N-terminal domain [81641]
         also includes extra transmembrane (linker) helix absent in plants and cyanobacteria subunits
         1. Cow (Bos taurus) [TaxId: 9913] [81638] (17)
            SQ P00157
         2. Chicken (Gallus gallus) [TaxId: 9031] [81639] (5)
         3. Baker's yeast (Saccharomyces cerevisiae) [TaxId: 4932] [81640] (9)
      2. Cytochrome b6 subunit of the cytochrome b6f complex [103498]
         1. Mastigocladus laminosus [TaxId: 83541] [103499] (6)
         2. Chlamydomonas reinhardtii [TaxId: 3055] [103500] (1)
   2. Formate dehydrogenase N, cytochrome (gamma) subunit [75645] (1)
      1. Formate dehydrogenase N, cytochrome (gamma) subunit [75646]
         1. Escherichia coli [TaxId: 562] [75647] (2)
2. Respiratory nitrate reductase 1 gamma chain [103501] (1)
   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
   uperfamily
   1. Respiratory nitrate reductase 1 gamma chain [103502] (1)
      1. Respiratory nitrate reductase 1 gamma chain [103503]
         1. Escherichia coli [TaxId: 562] [103504] (6)
            SQ P11350
3. Fumarate reductase respiratory complex transmembrane subunits [81343] (2)
   two distinct families: in one family the common fold is contained in a single-chain subunit, in the other it is formed by two chains
   uperfamily
   1. Fumarate reductase respiratory complex cytochrome b subunit, FrdC [56910] (1)
      duplication: consists of two structural repeats; the heme-binding sites are related by pseudo two fold symmetry
      1. Fumarate reductase respiratory complex cytochrome b subunit, FrdC [56911]
         1. Wolinella succinogenes [TaxId: 844] [56913] (8)
   2. Succinate dehydrogenase/Fumarate reductase transmembrane subunits (SdhC/FrdC and SdhD/FrdD) [81373] (4)
      consists of two homologous non-identical subunits that form a heterodimer; may or may not contain heme groups
      1. Succinate dehydrogenase subunit SdhC [82870]
         Cytochrome b556 subunit
         1. Escherichia coli [TaxId: 562] [82871] (3)
      2. Succinate dehydrogenase subunit SdhD [82872]
         membrane anchor protein
         1. Escherichia coli [TaxId: 562] [82873] (3)
      3. Fumarate reductase subunit FrdC [81370]
         1. Escherichia coli [TaxId: 562] [81369] (7)
            is not known to bind heme
      4. Fumarate reductase subunit FrdD [81372]
         1. Escherichia coli [TaxId: 562] [81371] (7)
            is not known to bind heme

Generated from scop database 1.75 with scopm 1.101 on Wed Jun 3 10:42:06 2009 Copyright © 1994-2009 The scop authors / scop@mrc-lmb.cam.ac.uk