<p>This family includes proteins encoded by the yabJ gene from <taxon tax_id="1423">Bacillus subtilis</taxon> that is required for adenine-mediated repression of purinebiosynthetic genes <i>in vivo</i> and codes for an acid-soluble, 14kDa protein.The structure of this protein has been solved [<cite idref="PUB00006517"/>] and the proteinis found to form a homotrimer. The trimer has a deep cleft that is a probably ligand binding site and possibly forms an enzymatic active site. However the ligand and reaction are unknown.</p><p>This entry represents a conserved region found towards the C terminus of these proteins.</p>