Description

IPR018198 is a ATP phosphoribosyltransferase, conserved site.

<p>ATP phosphoribosyltransferase ([ec:2.4.2.17]) is the enzyme that catalyzes 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 phosphoribosyltransferase 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 inihibition 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 prokayrotes, plants and fungi, this enzyme is a promising target for the development of novel antimicrobial compounds and herbicides.</p> <p>ATP phosphoribosyltransferase is found in two distinct 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]]. This entry represents the catalytic region of this enzyme.</p> <p>The structures of the long form enzymes from Escherichia coli ([swissprot:P60757]) and Mycobacterium tuberculosis ([swissprot:P60759]) have been determined [[cite:PUB00022501], [cite:PUB00028134]]. The enzyme itself exists in equilibrium between an active dimeric form, an inactive hexameric form and higher aggregates. Interconversion between the various forms is largely reversible and is influenced by the binding of the natural substrates and inhibitors of the enzyme. The two catalytic domains are linked by a two-stranded β-sheet and togther form a "periplasmic binding protein fold". A crevice between these domains contains the active site. The C-terminal domain is not directly involved in catalysis but appears to be involved the formation of hexamers, induced by the binding of inhibitors such as histidine to the enzyme, thus regulating activity.</p> <p>This entry represents the conserved site of ATP phosphoribosyltransferase enzymes.</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 2

Co-occuring domains 1

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