cd04587: CBS_pair_CAP-ED_DUF294_PBI_assoc (this model, PSSM-Id:73087 is obsolete and has been replaced by 341363)
This cd contains two tandem repeats of the cystathionine beta-synthase (CBS pair) domains associated with either the CAP_ED (cAMP receptor protein effector domain) family of transcription factors and the DUF294 domain or the PB1 (Phox and Bem1p) domain. Members of CAP_ED, include CAP which binds cAMP, FNR (fumarate and nitrate reductase) which uses an iron-sulfur cluster to sense oxygen, and CooA a heme containing CO sensor. In all cases binding of the effector leads to conformational changes and the ability to activate transcription. DUF294 is a putative nucleotidyltransferase with a conserved DxD motif. The PB1 domain adopts a beta-grasp fold, similar to that found in ubiquitin and Ras-binding domains. A motif, variously termed OPR, PC and AID, represents the most conserved region of the majority of PB1 domains, and is necessary for PB1 domain function. This function is the formation of PB1 domain heterodimers, although not all PB1 domain pairs associate. CBS is a small domain originally identified in cystathionine beta-synthase and subsequently found in a wide range of different proteins. CBS domains usually come in tandem repeats, which associate to form a so-called Bateman domain or a CBS pair which is reflected in this model. 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. It has been proposed that the CBS domain may play a regulatory role, although its exact function is unknown.
Jiyao W et al.(2023). "The conserved domain database in 2023.",