Protein Domain : Nitrogen regulatory PII-like, alpha/beta IPR011322

Type	Homologous_superfamily
Description	This superfamily represents a structural domain found in the nitrogen regulatory protein PII, in ATP phosphribosyltransferases (C-terminal domain), in the divalent ion tolerance protein CutA1, and in some bacterial hypothetical proteins. This domain consists of a ferredoxin-like alpha/beta sandwich, which forms trimeric structures with orthogonally packed β-sheets around a three-fold axis. PII is a tetrameric protein encoded by glnB that functions as a component of the adenylation cascade involved in the regulation of GS activity [ ]. PII helps regulate the level of glutamine synthetase in response to nitrogen source availability. In nitrogen-limiting conditions, PII is uridylylated to form PII-UMP, which allows the deadenylation of glutamine synthetase, thus activating the enzyme. Conversely, in nitrogen excess, PI-UMP is deuridylated to PII, promoting the adenylation and deactivation of glutamine synthetase [].ATP phosphoribosyltransferase is the first enzyme of the histidine pathway. It is allosterically regulated, controlling the flow of intermediates through the pathway. The C-terminal domain is the regulatory region of the protein, which binds the allosteric inhibitor histidine [ ].CutA1 functions in divalent ion tolerance in bacteria, plants and animals [ , ]. Divalent metal ions play key roles in all living organisms, serving as cofactors for many proteins involved in a variety of electron-transfer activities. In Escherichia coli it is thought to be involved in copper ion tolerance, excessive copper ions being toxic [].
Short Name	N-reg_PII-like_a/b