Please note: this site relies heavily on the use of javascript. Without a javascript-enabled browser, this site will not function correctly. Please enable javascript and reload the page, or switch to a different browser.
104  structures 3144  species 1  interaction 4692  sequences 46  architectures

Family: Rubredoxin (PF00301)

Summary: Rubredoxin

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

This is the Wikipedia entry entitled "Rubredoxin". More...

Rubredoxin Edit Wikipedia article

PDB 1s24 EBI.jpg
rubredoxin domain ii from pseudomonas oleovorans
Symbol Rubredoxin
Pfam PF00301
Pfam clan CL0045
InterPro IPR004039
SCOP 7rxn

Rubredoxins are a class of low-molecular-weight iron-containing proteins found in sulfur-metabolizing bacteria and archaea. Sometimes rubredoxins are classified as iron-sulfur proteins; however, in contrast to iron-sulfur proteins, rubredoxins do not contain inorganic sulfide. Like cytochromes, ferredoxins and Rieske proteins, rubredoxins participate in electron transfer in biological systems.


The 3-D structures of a number of rubredoxins have been solved. The fold belongs to the α+β class, with 2 α-helices and 2-3 β-strands. Rubredoxin active site contains an iron ion which is coordinated by the sulfurs of four conserved cysteine residues forming an almost regular tetrahedron. This is sometimes denoted as a [1Fe-0S] or an Fe1S0 system, in analogy to the nomenclature for iron-sulfur proteins. While the vast majority of rubredoxins are soluble, there exists a membrane-bound rubredoxin, referred to as rubredoxin A, in oxygenic photoautotrophs.[1]

Rubredoxins perform one-electron transfer processes. The central iron atom changes between the +2 and +3 oxidation states. In both oxidation states, the metal remains high spin, which helps to minimize structural changes. The reduction potential of a rubredoxin is typically in the range +50 mV to -50 mV.

This iron-sulphur protein is an electron carrier, and it is easy to distinguish its metallic centre changes: the oxidized state is reddish (due to a ligand metal charge transfer), while the reduced state is colourless (because the electron transition has an energy of the infrared level, which is imperceptible to the human eye).

Structural representation of a rubredoxin active site.

Rubredoxin in some biochemical reactions

EC camphor 1,2-monooxygenase [(+)-camphor,reduced-rubredoxin:oxygen oxidoreductase (1,2-lactonizing)]

(+)-bornane-2,5-dione + reduced rubredoxin + O2 = 5-oxo-1,2-campholide + oxidized rubredoxin + H2O

EC alkane 1-monooxygenase (alkane,reduced-rubredoxin:oxygen 1-oxidoreductase)

octane + reduced rubredoxin + O2 = 1-octanol + oxidized rubredoxin + H2O

EC superoxide reductase (rubredoxin:superoxide oxidoreductase)

reduced rubredoxin + superoxide + 2 H+ = rubredoxin + H2O2

EC rubredoxin—NAD+ reductase (rubredoxin:NAD+ oxidoreductase)

reduced rubredoxin + NAD+ = oxidized rubredoxin + NADH + H+

EC rubredoxin—NAD(P)+ reductase (rubredoxin:NAD(P)+ oxidoreductase)

reduced rubredoxin + NAD(P)+ = oxidized rubredoxin + NAD(P)H + H+

See also


  1. ^ Calderon, R. H., García-Cerdán, J. G., Malnoë, A., Cook, R., Russell, J. J., Gaw, C., Dent, R. M., de Vitry, C. and Niyogi, K. K. (July 2013). "A Conserved Rubredoxin Is Necessary for Photosystem II Accumulation in Diverse Oxygenic Photoautotrophs". The Journal of Biological Chemistry. 288: 26688–26696. doi:10.1074/jbc.M113.487629. PMC 3772215Freely accessible. PMID 23900844. 

Further reading

  • Stephen J. Lippard, Jeremy M. Berg, Principles of Bioinorganic Chemistry, University Science Books, 1994, ISBN 0-935702-72-5
  • J.J.R. Fraústo da Silva and R.J.P. Williams, The biological chemistry of the elements: The inorganic chemistry of life, 2nd Edition, Oxford University Press, 2001, ISBN 0-19-850848-4

External links

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Rubredoxin Provide feedback

No Pfam abstract.

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR024935

Rubredoxin is a low molecular weight iron-containing bacterial protein involved in electron transfer [PUBMED:2244884, PUBMED:1992166], sometimes replacing ferredoxin as an electron carrier [PUBMED:7726577]. Rubredoxins possess a 45- to 55-residue domain containing one iron atom tetrahedrally coordinated to four cysteinyl residues. Structural analysis of the domains have shown them to be folded into a short three-stranded antiparallel beta-sheet and a number of loops [PUBMED:3441010, PUBMED:1303768, PUBMED:7830611, PUBMED:8646540].

This entry represents the rubredoxin domain.

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

Loading domain graphics...

Pfam Clan

This family is a member of clan Rubredoxin (CL0045), which has the following description:

The Rubredoxin clan is comprised of three families:Rubredoxin, COX5B and desulforedoxin.Rubredoxin domains are small domains (5-6 kDa) and bind one iron atom tetrahedrally bound by four cysteine residues.Similar, desulforedoxin domains are small (4 kDa), but usually form homodimers. Each monomer binds one iron atom, but in a distorted tetrahedral arrangement. COX5B domains are membrane-anchored rubredoxin-like domains. The domain in the Rubredoxin clan are usually comprised of 2 alpha helixes and 2-3 beta strands.

The clan contains the following 5 members:

COX5B Desulfoferrod_N Methyltransf_13 Rubredoxin zf-CHCC


We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the UniProtKB sequence database, the NCBI sequence database, and our metagenomics sequence database. More...

View options

We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

Representative proteomes UniProt
Jalview View  View  View  View  View  View  View  View  View 
HTML View  View               
PP/heatmap 1 View               

1Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: ✓ available, x not generated, not available.

Format an alignment

Representative proteomes UniProt

Download options

We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

Representative proteomes UniProt
Raw Stockholm Download   Download   Download   Download   Download   Download   Download   Download   Download  
Gzipped Download   Download   Download   Download   Download   Download   Download   Download   Download  

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...


This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

Note: You can also download the data file for the tree.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation View help on the curation process

Seed source: Prosite
Previous IDs: rubredoxin;
Type: Domain
Sequence Ontology: SO:0000417
Author: Finn RD
Number in seed: 26
Number in full: 4692
Average length of the domain: 46.40 aa
Average identity of full alignment: 50 %
Average coverage of the sequence by the domain: 32.32 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 45638612 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 23.0 23.0
Trusted cut-off 23.0 23.0
Noise cut-off 22.9 22.9
Model length: 47
Family (HMM) version: 20
Download: download the raw HMM for this family

Species distribution

Sunburst controls


Weight segments by...

Change the size of the sunburst


Colour assignments

Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


Align selected sequences to HMM

Generate a FASTA-format file

Clear selection

This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

Loading sunburst data...

Tree controls


The tree shows the occurrence of this domain across different species. More...


Please note: for large trees this can take some time. While the tree is loading, you can safely switch away from this tab but if you browse away from the family page entirely, the tree will not be loaded.


There is 1 interaction for this family. More...



For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Rubredoxin domain has been found. There are 104 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.

Loading structure mapping...