CBS domains are small intracellular modules that pair together to form a stable globular domain. This family represents a single CBS domain. Pairs of these domains have been termed a Bateman domain. CBS domains have been shown to bind ligands with an adenosyl group such as AMP, ATP and S-AdoMet. 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 and the chloride channel CLC2 bind ATP.