Schultz et al. (1998) Proc. Natl. Acad. Sci. USA 95, 5857-5864
Letunic et al. (2012) Nucleic Acids Res , doi:10.1093/nar/gkr931

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Cyt-b5 Cytochrome b5-like Heme/Steroid binding domain

SMART accession number:	SM01117
Description:	This family includes heme binding domains from a diverse range of proteins. This family also includes proteins that bind to steroids. The family includes progesterone receptors such as O00264 ((PUBMED:9705155),(PUBMED:8774719)). Many members of this subfamily are membrane anchored by an N-terminal transmembrane alpha helix. This family also includes a domain in some chitin synthases. There is no known ligand for this domain in the chitin synthases.
Family alignment:	View or CHROMA formatCLUSTALW formatMSF formatFASTA formatPIR format

There are 3055 Cyt-b5 domains in 2883 proteins in SMART's nrdb database.

Click on the following links for more information.

• Evolution (species in which this domain is found)

• Click on to expand nodes. To display all proteins with a Cyt-b5 domain in a specific node, click on it.

  This tree shows only several representative species. The complete taxonomic breakdown of all proteins with Cyt-b5 domain is also avaliable.

  Useful shortcuts: Expand all nodes or Collapse tree
  Go to specific node: Anopheles gambiae, Arabidopsis thaliana, Caenorhabditis elegans, Drosophila melanogaster, Homo sapiens, Mus musculus, Rattus norvegicus, Saccharomyces cerevisiae, Takifugu rubripes

• Cellular role (predicted cellular role)

• Cellular role: signalling
  

• Structure (3D structures containing this domain)

• 3D Structures of Cyt-b5 domains in PDB

  PDB code	Main view	Title
  1aqa		Solution structure of reduced microsomal rat cytochrome b5, nmr, minimized average structure
  1aw3		The solution nmr structure of oxidized rat microsomal cytochrome b5, minimized average structure
  1awp		Rat outer mitochondrial membrane cytochrome b5
  1axx		The solution structure of oxidized rat microsomal cytochrome b5, nmr, 19 structures
  1b5a		Rat ferrocytochrome b5 a conformation, nmr, 1 structure
  1b5b		Rat ferrocytochrome b5 b conformation, nmr, 1 structure
  1b5m		Rat outer mitochondrial membrane cytochrome b5
  1bfx		The solution nmr structure of the b form of oxidized rat microsomal cytochrome b5, minimized average structure
  1blv		Solution structure of oxidized rat microsomal cytochrome b5 in the presence of 2 m guanidinium chloride: monitoring the early steps in protein unfolding
  1cxy		Structure and characterization of ectothiorhodospira vacuolata cytochrome b558, a prokaryotic homologue of cytochrome b5
  1cyo		Bovine cytochrome b(5)
  1do9		Solution structure of oxidized microsomal rabbit cytochrome b5. factors determining the heterogeneous binding of the heme.
  1ehb		Crystal structure of recombinant trypsin-solubilized fragment of cytochrome b5
  1es1		Crystal structure of val61his mutant of trypsin-solubilized fragment of cytochrome b5
  1eue		Rat outer mitochondrial membrane cytochrome b5
  1f03		Solution structure of oxidized bovine microsomal cytochrome b5 mutant (e44a, e48a, e56a, d60a) and its interaction with cytochrome c
  1f04		Solution structure of oxidized bovine microsomal cytochrome b5 mutant (e44a, e48a, e56a, d60a) and its interaction with cytochrome c
  1fcb		Molecular structure of flavocytochrome b2 at 2.4 angstroms resolution
  1hko		Nmr structure of bovine cytochrome b5
  1i5u		Solution structure of cytochrome b5 triple mutant (e48a/e56a/d60a)
  1i87		Solution structure of the water-soluble fragment of rat hepatic apocytochrome b5
  1i8c		Solution structure of the water-soluble fragment of rat hepatic apocytochrome b5
  1ib7		Solution structure of f35y mutant of rat ferro cytochrome b5, a conformation, ensemble of 20 structures
  1icc		Rat outer mitochondrial membrane cytochrome b5
  1iet		Apocytochrome b5, ph 6.2, 298 k, nmr, minimized average structure
  1ieu		Apocytochrome b5, ph 6.2, 298 k, nmr, 10 structures
  1j03		Solution structure of a putative steroid-binding protein from arabidopsis
  1j0q		Solution structure of oxidized bovine microsomal cytochrome b5 mutant v61h
  1jex		Solution structure of a67v mutant of rat ferro cytochrome b5
  1kbi		Crystallographic study of the recombinant flavin-binding domain of baker's yeast flavocytochrome b2: comparison with the intact wild-type enzyme
  1lco		X-ray structure of two complexes of the y143f flavocytochrome b2 mutant crystallized in the presence of lactate or phenyl-lactate
  1ldc		X-ray structure of two complexes of the y143f flavocytochrome b2 mutant crystallized in the presence of lactate or phenyl-lactate
  1lj0		Structure of quintuple mutant of the rat outer mitocondrial cytochrome b5.
  1lqx		Crystal structure of v45e mutant of cytochrome b5
  1lr6		Crystal structure of v45y mutant of cytochrome b5
  1ltd		The 2.6 angstroms refined structure of the escherichia coli recombinant saccharomyces cerevisiae flavocytochrome b2- sulphite complex
  1m20		Crystal structure of f35y mutant of trypsin-solubilized fragment of cytochrome b5
  1m2i		Crystal structure of e44a/e56a mutant of cytochrome b5
  1m2m		Crystal structure of e44a/e48a/e56a/d60a mutant of cytochrome b5
  1m59		Crystal structure of p40v mutant of trypsin-solubilized fragment of cytochrome b5
  1mj4		Crystal structure analysis of the cytochrome b5 domain of human sulfite oxidase
  1mny		Dimethyl propionate ester heme-containing cytochrome b5
  1nx7		Solution structure of oxidized bovine microsomal cytochrome b5
  1sh4		Solution structure of oxidized bovine microsomal cytochrome b5 mutant v45h
  1sox		Sulfite oxidase from chicken liver
  1sze		L230a mutant flavocytochrome b2 with benzoylformate
  1szf		A198g:l230a mutant flavocytochrome b2 with pyruvate bound
  1szg		A198g:l230a flavocytochrome b2 with sulfite bound
  1t0g		Hypothetical protein at2g24940.1 from arabidopsis thaliana has a cytochrome b5 like fold
  1u9m		Crystal structure of f58w mutant of cytochrome b5
  1u9u		Crystal structure of f58y mutant of cytochrome b5
  1x3x		Crystal structure of cytochrome b5 from ascaris suum
  2axx		The solution structure of oxidized rat microsomal cytochrome b5, nmr, 21 structures
  2i89		Structure of septuple mutant of rat outer mitochondrial membrane cytochrome b5
  2i96		Solution structure of the oxidized microsomal human cytochrome b5
  2ibj		Structure of house fly cytochrome b5
  2keo		Solution nmr structure of human protein hs00059, cytochrome- b5-like domain of the herc2 e3 ligase. northeast structural genomics consortium (nesg) target ht98a
  2oz0		Mechanistic and structural studies of h373q flavocytochrome b2: effects of mutating the active site base

• Links (links to other resources describing this domain)

• PFAM	Cyt-b5

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