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236  structures 11389  species 5  interactions 21339  sequences 65  architectures

Clan: HO (CL0230)


Heme oxygenase-like superfamily Add an annotation

This clan includes the Heme oxygenase family as well as the TENA/THI-4/PQQC family that are less well characterised [2].

This clan contains 5 families and the total number of domains in the clan is 21339. The clan was built by A Bateman.

Literature references

  1. Benach J, Edstrom WC, Lee I, Das K, Cooper B, Xiao R, Liu J, Rost B, Acton TB, Montelione GT, Hunt JF; , Acta Crystallogr D Biol Crystallogr. 2005;61:589-598.: The 2.35 A structure of the TenA homolog from Pyrococcus furiosus supports an enzymatic function in thiamine metabolism. PUBMED:15858269 EPMC:15858269
  2. Schuller DJ, Wilks A, Ortiz de Montellano PR, Poulos TL; , Nat Struct Biol. 1999;6:860-867.: Crystal structure of human heme oxygenase-1. PUBMED:10467099 EPMC:10467099


This clan contains the following 5 member families:

DUF3050 DUF3865 Haem_oxygenas_2 Heme_oxygenase TENA_THI-4

External database links

Domain organisation

Below is a listing of the unique domain organisations or architectures from this clan. More...

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The table below shows the number of occurrences of each domain throughout the sequence database. More...

Pfam family Num. domains Alignment
TENA_THI-4 (PF03070) 12566 (58.9%) View
Haem_oxygenas_2 (PF14518) 5172 (24.2%) View
Heme_oxygenase (PF01126) 3263 (15.3%) View
DUF3050 (PF11251) 307 (1.4%) View
DUF3865 (PF12981) 31 (0.1%) View
Total: 5 Total: 21339 Clan alignment

Please note: Clan alignments can be very large and can cause problems for some browsers. Read the note above before viewing.

Family relationships

This diagram shows the relationships between members of this clan. More...

Species distribution

Tree controls


This tree shows the occurrence of the domains in this clan across different species. More...



There are 5 interactions for this clan. More...

Interacting families
Haem_oxygenas_2 Haem_oxygenas_2
Heme_oxygenase Heme_oxygenase
HOASN Haem_oxygenas_2


For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the MSD group, to allow us to map Pfam domains onto UniProt three-dimensional structures. The table below shows the mapping between the Pfam families in this clan, the corresponding UniProt entries, and the region of the three-dimensional structures that are available for that sequence.

Loading structure mapping...