PROSITE documentation PDOC50933 [for PROSITE entry PS50933]

CHRD domain profile

The CHRD (after the gene name of chordin) is a domain of about 120-amino acid residues that is found in:

• Vertebrate chordin, an inhibitor of bone morphogenetic proteins,
• Ascidian orthologue of chordin,
• Drosophila short gastrulation (SOG), the orthologue of chordin,
• Microbial proteins from cyanobacteria, soil bacteria and human pathogens.

Whereas chordin contains four copies of the CHRD domain, most of the bacterial CHRD containing proteins have only a single copy. This indicates that the CHRD domain is an independent domain and folding unit. The CHRD domain can be found in stand-alone form, or in association with other domains such as the von Willebrand factor type C domain (see <PDOC00928>) and the hemolysin-type calcium-binding domain (see <PDOC00293>). The function of the CHRD domain is not yet known [1].

The most conserved feature of the CHRD domain is the C-terminal G-E-[IL]-R-C-Q-[VIL] motif. No single residue is fully conserved between all the domains, but several highly conserved positions can be found between the microbial CHRD domains. Many of these residues are also present in the third repeat of chordin, which raises the possibility that the other domains in chordin have lost the original function and gained a new, perhaps structural or regulatory role. The CHRD domain has been predicted to have an immunoglobulin-like β-barrel structure [1].

The profile we developed covers the entire CHRD domain.