Two tandem repeats of the cystathionine beta-synthase (CBS pair) domains the majority of which are associated with the CorC_HlyC domain
This cd contains two tandem repeats of the cystathionine beta-synthase (CBS pair) domains the majority of which are associated with the CorC_HlyC domain. CorC_HlyC is a transporter associated domain. This small domain is found in Na+/H+ antiporters, in proteins involved in magnesium and cobalt efflux, and in association with some proteins of unknown function. The function of the CorC_HlyC domain is uncertain but it might be involved in modulating transport of ion substrates. These CBS domains are found in highly conserved proteins that either have unknown function or are puported to be hemolysins, exotoxins involved in lysis of red blood cells in vitro. The CBS domain, named after human CBS, is a small domain originally identified in cystathionine beta-synthase and is subsequently found in a wide range of different proteins. CBS domains usually occur in tandem repeats. They associate to form a so-called Bateman domain or a CBS pair based on crystallographic studies in bacteria. The CBS pair was used as a basis for this cd hierarchy since the human CBS proteins can adopt the typical core structure and form an intramolecular CBS pair. The interface between the two CBS domains forms a cleft that is a potential ligand binding site. The CBS pair coexists with a variety of other functional domains and this has been used to help in its classification here. It has been proposed that the CBS domain may play a regulatory role, although its exact function is unknown. Mutations of conserved residues within this domain are associated with a variety of human hereditary diseases, including congenital myotonia, idiopathic generalized epilepsy, hypercalciuric nephrolithiasis, and classic Bartter syndrome (CLC chloride channel family members), Wolff-Parkinson-White syndrome (gamma 2 subunit of AMP-activated protein kinase), retinitis pigmentosa (IMP dehydrogenase-1), and homocystinuria (cystathionine beta-synthase).
Jiyao W et al.(2023). "The conserved domain database in 2023.",