cd04602

This cd contains two tandem repeats of the cystathionine beta-synthase (CBS pair) domains in the inosine 5' monophosphate dehydrogenase (IMPDH) protein. IMPDH is an essential enzyme that catalyzes the first step unique to GTP synthesis, playing a key role in the regulation of cell proliferation and differentiation. 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. Mutations of conserved residues within this domain in IMPDH have been associated with retinitis pigmentosa.