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75  structures 1594  species 1  interaction 3168  sequences 57  architectures

Clan: HNOX-like (CL0210)


Heme NO and oxygen binding like Add an annotation

This clan contains families that bind small molecules and are predominantly involved in signalling. Members include the heme NO binding domain. This domain is related to soluble guanylate cyclases and is mainly alpha helical in structure. Other members of this clan include V4R, which is predicted to be a small molecule binding domain, and a domain often found adjacent to this that is found on activators of aromatic catabolism, and on signalling molecules.

This clan contains 3 families and the total number of domains in the clan is 3168. The clan was built by J Mistry.

Literature references

  1. Iyer LM, Anantharaman V, Aravind L; , BMC Genomics 2003;4:5.: Ancient conserved domains shared by animal soluble guanylyl cyclases and bacterial signaling proteins. PUBMED:12590654 EPMC:12590654
  2. Pellicena P, Karow DS, Boon EM, Marletta MA, Kuriyan J; , Proc Natl Acad Sci U S A 2004;101:12854-12859.: Crystal structure of an oxygen-binding heme domain related to soluble guanylate cyclases. PUBMED:15326296 EPMC:15326296


This clan contains the following 3 member families:


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
HNOB (PF07700) 1441 (45.5%) View
V4R (PF02830) 1166 (36.8%) View
XylR_N (PF06505) 561 (17.7%) View
Total: 3 Total: 3168 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...



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

Interacting families


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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