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Cytochrome b5-like heme/steroid binding domain superfamily

SCOP classification
Root:   SCOP hierarchy in SUPERFAMILY [ 0] (11)
Class:   Alpha and beta proteins (a+b) [ 53931] (376)
Fold:   Cytochrome b5-like heme/steroid binding domain [ 55855]
Superfamily:   Cytochrome b5-like heme/steroid binding domain [ 55856] (2)
Families:   Cytochrome b5 [ 55857] (4)
  Steroid-binding domain [ 103222]


Superfamily statistics
Genomes (659) Uniprot 2014_06 PDB chains (SCOP 1.75)
Domains 8,832 10,602 34
Proteins 8,656 10,381 34


Functional annotation
General category Metabolism
Detailed category E- transfer

Document:
Function annotation of SCOP domain superfamilies

Gene Ontology (high-quality)

(show details)
GO termFDR (singleton)FDR (all)SDFO levelAnnotation (direct or inherited)
Molecular Function (MF)electron carrier activity0.0000082570.0000009415InformativeDirect

Document: GO annotation of SCOP domains

Gene Ontology (high-coverage)

(show details)
GO term FDR (all) SDFO level Annotation (direct or inherited)
Biological Process (BP) biosynthetic process 0.00000002005 Least Informative Direct
Biological Process (BP) single-organism metabolic process 0.000000000000001945 Least Informative Direct
Biological Process (BP) biological regulation 1 Least Informative Inherited
Biological Process (BP) single-organism cellular process 0.002002 Least Informative Inherited
Biological Process (BP) organonitrogen compound metabolic process 1 Least Informative Inherited
Biological Process (BP) primary metabolic process 1 Least Informative Inherited
Biological Process (BP) lipid metabolic process 0 Moderately Informative Direct
Biological Process (BP) monocarboxylic acid metabolic process 0.0000000000000446 Moderately Informative Direct
Biological Process (BP) small molecule biosynthetic process 0.00000000001342 Moderately Informative Direct
Biological Process (BP) regulation of cellular biosynthetic process 1 Moderately Informative Inherited
Biological Process (BP) reproduction 0.5704 Moderately Informative Inherited
Biological Process (BP) fatty acid metabolic process 0.00000000000005766 Informative Direct
Biological Process (BP) monocarboxylic acid biosynthetic process 0 Informative Direct
Biological Process (BP) regulation of lipid metabolic process 0.001143 Informative Inherited
Biological Process (BP) growth 0.1748 Informative Inherited
Biological Process (BP) membrane lipid metabolic process 0.5358 Informative Inherited
Biological Process (BP) unsaturated fatty acid biosynthetic process 0 Highly Informative Direct
Biological Process (BP) sphingolipid biosynthetic process 0.00000047 Highly Informative Direct
Biological Process (BP) regulation of steroid biosynthetic process 0.000001004 Highly Informative Direct
Molecular Function (MF) binding 1 Least Informative Inherited
Molecular Function (MF) oxidoreductase activity 0 Moderately Informative Direct
Molecular Function (MF) electron carrier activity 0.0000009415 Informative Direct
Molecular Function (MF) tetrapyrrole binding 0.00000002776 Informative Direct
Molecular Function (MF) oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxyge 0 Highly Informative Direct
Molecular Function (MF) heme binding 0.00000001816 Highly Informative Direct
Cellular Component (CC) intracellular organelle part 0.668 Least Informative Inherited
Cellular Component (CC) intracellular membrane-bounded organelle 0.3808 Least Informative Inherited
Cellular Component (CC) membrane 0.1286 Least Informative Inherited
Cellular Component (CC) cytoplasmic part 0.08443 Least Informative Inherited
Cellular Component (CC) endoplasmic reticulum 0.00000000031 Moderately Informative Direct
Cellular Component (CC) endoplasmic reticulum membrane 0.00000009323 Informative Direct

Document: GO annotation of SCOP domains

Enzyme Commission (EC)

(show details)
EC termFDR (all)SDEO levelAnnotation (direct or inherited)
Enzyme Commission (EC)Oxidoreductases0Least InformativeDirect
Enzyme Commission (EC)Acting on a sulfur group of donors0.01363Moderately InformativeInherited
Enzyme Commission (EC)Acting on NADH or NADPH0.0902Moderately InformativeInherited
Enzyme Commission (EC)With NAD(+) or NADP(+) as acceptor0InformativeDirect
Enzyme Commission (EC)Nitrate reductase (NADH)0Highly InformativeDirect
Enzyme Commission (EC)Sulfite oxidase0Highly InformativeDirect
Enzyme Commission (EC)With a heme protein as acceptor0.00000000000002642Highly InformativeDirect
Enzyme Commission (EC)Nitrate reductase (NADPH)0.0000000004944Highly InformativeDirect

Document: EC annotation of SCOP domains

Human Phenotype (HP)

(show details) Document: HP annotation of SCOP domains

Worm Phenotype (WP)

(show details) Document: WP annotation of SCOP domains

Yeast Phenotype (YP)

(show details) Document: YP annotation of SCOP domains

Fly Phenotype (FP)

(show details)
FP termFDR (all)SDFP levelAnnotation (direct or inherited)
Fly Phenotype (FP)viable0Least InformativeDirect
Fly Phenotype (FP)fertile0Moderately InformativeDirect

Document: FP annotation of SCOP domains

Xenopus Anatomy (XA)

(show details)
XA termFDR (all)SDXA levelAnnotation (direct or inherited)
Xenopus ANatomical entity (XAN)genital system0Least InformativeDirect
Xenopus ANatomical entity (XAN)nervous system0Least InformativeDirect
Xenopus ANatomical entity (XAN)male organism0Least InformativeDirect
Xenopus ANatomical entity (XAN)head0Least InformativeDirect
Xenopus ANatomical entity (XAN)gonad0Least InformativeDirect

Document: XA annotation of SCOP domains

Arabidopsis Plant Ontology (AP)

(show details) Document: AP annotation of SCOP domains

Enzyme Commission (EC)

(show details)
EC termFDR (all)SDEC levelAnnotation (direct or inherited)
Enzyme Commission (EC)Oxidoreductases0Least InformativeDirect
Enzyme Commission (EC)Acting on other nitrogenous compounds as donors0InformativeDirect
Enzyme Commission (EC)Acting on paired donors, with incorporation or reduction of molecular oxygen. The oxygen incorporate2.486e-16InformativeDirect
Enzyme Commission (EC)Acting on a sulfur group of donors0.09019InformativeInherited
Enzyme Commission (EC)Acting on NADH or NADPH0.4786InformativeInherited
Enzyme Commission (EC)With NAD(+) or NADP(+) as acceptor0Highly InformativeDirect
Enzyme Commission (EC)With oxygen as acceptor9.829e-16Highly InformativeDirect
Enzyme Commission (EC)With a heme protein as acceptor0.0000000000006204Highly InformativeDirect

Document: EC annotation of SCOP domains

UniProtKB KeyWords (KW)

(show details)
KW termFDR (all)SDKW levelAnnotation (direct or inherited)
Biological processTransport0Least InformativeDirect
Biological processLipid metabolism0Moderately InformativeDirect
Biological processElectron transport0InformativeDirect
Biological processFatty acid metabolism0.00000000001424InformativeDirect
Biological processNeurogenesis0.000007347InformativeDirect
Biological processLipid biosynthesis0.04005InformativeInherited
Biological processNitrate assimilation0Highly InformativeDirect
Biological processSphingolipid metabolism0.0000000005938Highly InformativeDirect
Cellular componentMembrane0Least InformativeDirect
Cellular componentEndoplasmic reticulum0Moderately InformativeDirect
Cellular componentMitochondrion0.00002436Moderately InformativeDirect
Cellular componentMicrosome0.00000000000584Highly InformativeDirect
DomainTransmembrane0Least InformativeDirect
Molecular functionMetal-binding0Least InformativeDirect
Molecular functionFlavoprotein0Moderately InformativeDirect
Molecular functionIron0Moderately InformativeDirect
Molecular functionLipid-binding0.00000000003979Moderately InformativeDirect
Molecular functionNAD0.00000006427Moderately InformativeDirect
Molecular functionHeme0InformativeDirect
Molecular functionMolybdenum0InformativeDirect
Molecular functionFAD0.00005863InformativeDirect
Molecular functionSteroid-binding0Highly InformativeDirect
Post-translational modificationOxidoreductase0Moderately InformativeDirect
Post-translational modificationReceptor0.0007907Moderately InformativeDirect
Post-translational modificationAcetylation0.0005716Least InformativeDirect

Document: KW annotation of SCOP domains

UniProtKB UniPathway (UP)

(show details)
UP termFDR (all)SDUP levelAnnotation (direct or inherited)
UniPathway (UP)lipid metabolism0Least InformativeDirect
UniPathway (UP)fatty acid metabolism0.00000001299Moderately InformativeDirect
UniPathway (UP)energy metabolism0.000003484Moderately InformativeDirect
UniPathway (UP)lipid biosynthesis0.3834Moderately InformativeInherited
UniPathway (UP)membrane lipid metabolism1Moderately InformativeInherited
UniPathway (UP)fatty acid biosynthesis0InformativeDirect
UniPathway (UP)sphingolipid metabolism0.00000003169Highly InformativeDirect

Document: UP annotation of SCOP domains

InterPro annotation
Cross references IPR001199 SSF55856 Protein matches
Abstract Cytochromes b5 are ubiquitous electron transport proteins found in animals, plants and yeasts [PubMed2752049]. The microsomal and mitochondrial variants are membrane-bound, while those from erythrocytes and other animal tissues are water-soluble [PubMed4030743, PubMed8439576].

The 3D structure of bovine cyt b5 is known, the fold belonging to the alpha+beta class, with 5 strands and 5 short helices forming a framework for supporting a central haem group [PubMed1167544]. The cytochrome b5 domain is similar to that of a number of oxidoreductases, such as plant and fungal nitrate reductases, sulphite oxidase, yeast flavocytochrome b2 (L-lactate dehydrogenase) and plant cyt b5/acyl lipid desaturase fusion protein.


InterPro database


PDBeMotif information about ligands, sequence and structure motifs
Cross references PDB entries
Ligand binding statistics
Nucleic-acid binding statistics
Occurrence of secondary structure elements
Occurrence of small 3D structural motifs

PDBeMotif resource

Jump to [ Top of page · SCOP classification · InterPro annotation · PDBeMotif links · Functional annotation · Gene Ontology (high-quality) · Gene Ontology (high-coverage) · Enzyme Commission (EC) · Human Phenotype (HP) · Worm Phenotype (WP) · Yeast Phenotype (YP) · Fly Phenotype (FP) · Xenopus Anatomy (XA) · Arabidopsis Plant Ontology (AP) · Enzyme Commission (EC) · UniProtKB KeyWords (KW) · UniProtKB UniPathway (UP) ]

Internal database links

Browse genome assignments for this superfamily. The SUPERFAMILY hidden Markov model library has been used to carry out SCOP domain assignments to all genomes at the superfamily level.


Alignments of sequences to 10 models in this superfamily are available by clicking on the 'Alignments' icon above. PDB sequences less than 40% identical are shown by default, but any other sequence(s) may be aligned. Select PDB sequences, genome sequences, or paste in or upload your own sequences.


Browse and view proteins in genomes which have different domain combinations including a Cytochrome b5-like heme/steroid binding domain domain.


Examine the distribution of domain superfamilies, or families, across the major taxonomic kingdoms or genomes within a kingdom. This gives an immediate impression of how superfamilies, or families, are restricted to certain kingdoms of life.


Explore domain occurrence network where nodes represent genomes and edges are domain architectures (shared between genomes) containing the superfamily of interest.

There are 10 hidden Markov models representing the Cytochrome b5-like heme/steroid binding domain superfamily. Information on how the models are built, and plots showing hydrophobicity, match emmission probabilities and insertion/deletion probabilities can be inspected.


Jump to [ Top of page · SCOP classification · InterPro annotation · PDBeMotif links · Functional annotation · Gene Ontology (high-quality) · Gene Ontology (high-coverage) · Enzyme Commission (EC) · Human Phenotype (HP) · Worm Phenotype (WP) · Yeast Phenotype (YP) · Fly Phenotype (FP) · Xenopus Anatomy (XA) · Arabidopsis Plant Ontology (AP) · Enzyme Commission (EC) · UniProtKB KeyWords (KW) · UniProtKB UniPathway (UP) · Internal database links ]