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245  structures 5848  species 0  interactions 18745  sequences 74  architectures

Clan: COX1-like (CL0714)


Cytochrome c oxidase subunit I-like superfamily Add an annotation

This superfamily includes the catalytic subunit of all haem-copper respiratory oxidases, which is equivalent to mammalian cytochrome c oxidase subunit I (COX1). The bimetallic centre (formed by a high-spin haem and copper B) and the low-spin haem, ligated to six conserved histidine residues near the outer side of four transmembrane spans within COXI is common to all members [1,2]. Bacterial nitric oxide reductases (NORs), involved in microbial denitrification, are divided in cytochrome c–dependent NOR (cNOR) and quinol-dependent NOR (qNOR), based on their electron donor [2].

This clan contains 2 families and the total number of domains in the clan is 18745. The clan was built by S Chuguransky.

Literature references

  1. Castresana J, Lubben M, Saraste M, Higgins DG;, EMBO J. 1994;13:2516-2525.: Evolution of cytochrome oxidase, an enzyme older than atmospheric oxygen. PUBMED:8013452 EPMC:8013452
  2. Gopalasingam CC, Johnson RM, Chiduza GN, Tosha T, Yamamoto M, Shiro Y, Antonyuk SV, Muench SP, Hasnain SS;, Sci Adv. 2019;5:eaax1803.: Dimeric structures of quinol-dependent nitric oxide reductases (qNORs) revealed by cryo-electron microscopy. PUBMED:31489376 EPMC:31489376


This clan contains the following 2 member families:


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
COX1 (PF00115) 16920 (90.3%) View
NnrS (PF05940) 1825 (9.7%) View
Total: 2 Total: 18745 Clan alignment

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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...



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.

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