Protein Domain : Cystathionine beta-synthase, C-terminal domain IPR046353

Type	Domain
Description	This entry represents the C-terminal region of Cystathionine beta-synthase (CBS), which includes two tandem repeats of the CBS domain. CBS is an hydro-lyase that catalyses the first step of the transsulfuration pathway, where the hydroxyl group of L-serine is displaced by L-homocysteine in a beta-replacement reaction to form L-cystathionine, the precursor of L-cysteine. This catabolic route allows the elimination of L-methionine and the toxic metabolite L-homocysteine [ , , ]. This protein is also involved in the production of hydrogen sulphide, a gasotransmitter with signalling and cytoprotective effects on neurons [, ]. CBS domains are evolutionarily conserved structural domains found in a variety of non functionally-related proteins from all kingdoms of life. These domains pair together to form a intramolecular dimeric structure (CBS pair), termed Bateman domain [ , , , ]. CBS domains have been shown to bind mainly ligands with an adenosyl group such as AMP, ATP and S-AdoMet, but may also bind metal ions, or nucleic acids [, ]. Hence, they play an essential role in the regulation of the activities of numerous proteins, and mutations in them are associated with several hereditary diseases [, , ]. CBS domains are found attached to a wide range of other protein domains suggesting that CBS domains may play a regulatory role making proteins sensitive to adenosyl-carrying ligands. The region containing the CBS domains in cystathionine-beta synthase is involved in regulation by S-AdoMet []. CBS domain pairs from AMPK bind AMP or ATP []. The CBS domains from IMPDH, which bind ATP, have shown to have a role in the regulation of adenylate nucleotide synthesis [, ].
Short Name	CBS_C