Description

IPR001348 is a ATP phosphoribosyltransferase HisG.

<p>ATP phosphoribosyltransferase (ATP-PRT, [ec:2.4.2.17]) is the enzyme that catalyses the first step in the biosynthesis of histidine in bacteria, fungi and plants as shown below. It is a member of the larger phosphoribosyltransferase superfamily of enzymes which catalyse the condensation of 5-phospho-alpha-D-ribose 1-diphosphate with nitrogenous bases in the presence of divalent metal ions [[cite:PUB00028083]]. <reaction>ATP + 5-phospho-alpha-D-ribose 1-diphosphate = 1-(5-phospho-D-ribosyl)-ATP + diphosphate</reaction> Histidine biosynthesis is an energetically expensive process and ATP-PRT activity is subject to control at several levels. Transcriptional regulation is based primarily on nutrient conditions and determines the amount of enzyme present in the cell, while feedback inhibition rapidly modulates activity in response to cellular conditions. The enzyme has been shown to be inhibited by 1-(5-phospho-D-ribosyl)-ATP, histidine, ppGpp (a signal associated with adverse environmental conditions) and ADP and AMP (which reflect the overall energy status of the cell). As this pathway of histidine biosynthesis is present only in prokaryotes, plants and fungi, this enzyme is a promising target for the development of novel antimicrobial compounds and herbicides.</p> <p>ATP-PRT come in two forms: a long form containing two catalytic domains and a C-terminal regulatory domain, and a short form in which the regulatory domain is missing. The long form is catalytically competent, but in organisms with the short form, a histidyl-tRNA synthetase paralogue, HisZ, is required for enzyme activity [[cite:PUB00028139]].</p> <p>The enzyme was initially thought to exist in equilibrium between an active dimeric form, an inactive hexameric form and higher aggregates [[cite:PUB00022501], [cite:PUB00028134]]. However, it has been shown later that this protein is a hexamer in equilibrium between an open and probably active state and a more compact closed and presumably inhibited form. These conformational changes are related to the allosteric inhibition by histidine. The ATP-PRT from Campylobacter jejuni is organised into three domains. The first two domains form a bilobal core unit that harbours the catalytic site in the cleft between them, where the binding of ATP and AMP is observed, and the C-terminal is a regulatory ACT domain, which binds histidine [[cite:PUB00103843], [cite:PUB00103845], [cite:PUB00103844]].</p>

This description is obtained from EB-eye REST.

Associated GO terms

GO predictions are based solely on the InterPro-to-GO mappings published by EMBL-EBI, which are in turn based on the mapping of predicted domains to the InterPro dataset. The InterPro-to-GO mapping was last updated on April 27, 2020, while the GO metadata was last updated on April 27, 2020.

Associated Lotus transcripts 3

Co-occuring domains 1

A list of co-occurring predicted domains within the L. japonicus gene space: