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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 (653) Uniprot 2014_06 PDB chains (SCOP 1.75)
Domains 8,673 10,602 34
Proteins 8,509 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)
Biological Process (BP)single-organism metabolic process0.017340.000000008615Least InformativeInherited
Biological Process (BP)monocarboxylic acid metabolic process0.073880.00000155Moderately InformativeInherited
Biological Process (BP)cellular lipid metabolic process0.0073920.000000000000003741Moderately InformativeInherited
Biological Process (BP)fatty acid metabolic process0.00014290.0006316InformativeDirect
Molecular Function (MF)oxidoreductase activity0.0018490Moderately InformativeInherited
Molecular Function (MF)electron carrier activity0.0000012840.000000001505InformativeDirect
Molecular Function (MF)oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxyge0.00028030.000001266Highly InformativeDirect

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) single-organism metabolic process 0.000000008615 Least Informative Direct
Biological Process (BP) biosynthetic process 0.001704 Least Informative Inherited
Biological Process (BP) developmental process 1 Least Informative Inherited
Biological Process (BP) organic cyclic compound metabolic process 1 Least Informative Inherited
Biological Process (BP) nitrogen compound metabolic process 0.9068 Least Informative Inherited
Biological Process (BP) lipid biosynthetic process 0.00000000000618 Moderately Informative Direct
Biological Process (BP) monocarboxylic acid metabolic process 0.00000155 Moderately Informative Direct
Biological Process (BP) cellular lipid metabolic process 0.000000000000003741 Moderately Informative Direct
Biological Process (BP) single-organism biosynthetic process 0.000001943 Moderately Informative Direct
Biological Process (BP) single-organism developmental process 1 Moderately Informative Inherited
Biological Process (BP) reproduction 1 Moderately Informative Inherited
Biological Process (BP) organic hydroxy compound metabolic process 0.006754 Moderately Informative Inherited
Biological Process (BP) organic cyclic compound biosynthetic process 0.6591 Moderately Informative Inherited
Biological Process (BP) carbohydrate derivative metabolic process 0.2989 Moderately Informative Inherited
Biological Process (BP) fatty acid metabolic process 0.0006316 Informative Direct
Biological Process (BP) monocarboxylic acid biosynthetic process 0.000005101 Informative Direct
Biological Process (BP) growth 0.1592 Informative Inherited
Biological Process (BP) organic hydroxy compound biosynthetic process 0.005532 Informative Inherited
Biological Process (BP) alcohol metabolic process 0.1466 Informative Inherited
Biological Process (BP) membrane lipid metabolic process 0.08418 Informative Inherited
Biological Process (BP) steroid biosynthetic process 0.0003429 Highly Informative Direct
Biological Process (BP) sterol metabolic process 0.000001743 Highly Informative Direct
Biological Process (BP) unsaturated fatty acid metabolic process 0.000008367 Highly Informative Direct
Biological Process (BP) alcohol biosynthetic process 0.02694 Highly Informative Inherited
Molecular Function (MF) binding 1 Least Informative Inherited
Molecular Function (MF) oxidoreductase activity 0 Moderately Informative Direct
Molecular Function (MF) electron carrier activity 0.000000001505 Informative Direct
Molecular Function (MF) tetrapyrrole binding 0.000003349 Informative Direct
Molecular Function (MF) oxidoreductase activity, acting on NAD(P)H 0.1096 Informative Inherited
Molecular Function (MF) oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxyge 0.000001266 Highly Informative Direct
Molecular Function (MF) heme binding 0.000002522 Highly Informative Direct
Cellular Component (CC) intracellular organelle part 1 Least Informative Inherited
Cellular Component (CC) intracellular membrane-bounded organelle 1 Least Informative Inherited
Cellular Component (CC) cytoplasmic part 0.1141 Least Informative Inherited
Cellular Component (CC) membrane 0.5915 Least Informative Inherited
Cellular Component (CC) endoplasmic reticulum 0.000000002513 Moderately Informative Direct
Cellular Component (CC) endomembrane system 0.0008164 Moderately Informative Direct
Cellular Component (CC) organelle membrane 0.00002592 Moderately Informative Direct
Cellular Component (CC) endoplasmic reticulum membrane 0.0000002002 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)
WP termFDR (all)SDWP levelAnnotation (direct or inherited)
Worm Phenotype (WP)organ system development variant0.004696Moderately InformativeInherited

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)central 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 oxygen0.0006651InformativeDirect
Enzyme Commission (EC)Acting on a sulfur group of donors0.02587InformativeInherited
Enzyme Commission (EC)Acting on NADH or NADPH0.2006InformativeInherited
Enzyme Commission (EC)With NAD(+) or NADP(+) as acceptor0Highly InformativeDirect
Enzyme Commission (EC)With oxygen as acceptor0Highly InformativeDirect
Enzyme Commission (EC)With a heme protein as acceptor0.00000000000007519Highly 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 metabolism0.00000003607InformativeDirect
Biological processNeurogenesis0.00002229InformativeDirect
Biological processLipid biosynthesis0.11InformativeInherited
Biological processNitrate assimilation0Highly InformativeDirect
Biological processSphingolipid metabolism0.00000002606Highly InformativeDirect
Cellular componentMembrane0Least InformativeDirect
Cellular componentEndoplasmic reticulum0Moderately InformativeDirect
Cellular componentMitochondrion0.00000687Moderately InformativeDirect
Cellular componentMicrosome0.00000000002964Highly InformativeDirect
DomainTransmembrane0Least InformativeDirect
Molecular functionMetal-binding0Least InformativeDirect
Molecular functionFlavoprotein0Moderately InformativeDirect
Molecular functionIron0Moderately InformativeDirect
Molecular functionNAD0.00000000004991Moderately InformativeDirect
Molecular functionHeme0InformativeDirect
Molecular functionMolybdenum0InformativeDirect
Molecular functionLipid-binding0.000000000002152InformativeDirect
Molecular functionFAD0.00004203InformativeDirect
Molecular functionSteroid-binding0Highly InformativeDirect
Post-translational modificationOxidoreductase0Moderately InformativeDirect
Post-translational modificationReceptor0.0002472Moderately InformativeDirect

Document: KW 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) ]

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) · Internal database links ]