|PROSITE documentation PDOC00536 [for PROSITE entry PS00614]|
Indole-3-glycerol phosphate synthase (EC 18.104.22.168) (IGPS) catalyzes the fourth step in the biosynthesis of tryptophan: the ring closure of 1-(2-carboxy-phenylamino)-1-deoxyribulose into indol-3-glycerol-phosphate.
In some bacteria, IGPS is a single chain enzyme. In others - such as Escherichia coli - it is the N-terminal domain of a bifunctional enzyme that also catalyzes N-(5'-phosphoribosyl)anthranilate isomerase (PRAI) activity, the third step of tryptophan biosynthesis. In fungi, IGPS is the central domain of a trifunctional enzyme that also contains a PRAI C-terminal domain and a glutamine amidotransferase N-terminal domain.
The N-terminal section of IGPS contains a highly conserved region which X-ray crystallography studies  have shown to be part of the active site cavity. We use this region as a signature pattern for IGPS.Last update:
April 2006 / Pattern revised.
PROSITE method (with tools and information) covered by this documentation:
|1||Authors||Wilmanns M., Priestle J.P., Niermann T., Jansonius J.N.|
|Title||Three-dimensional structure of the bifunctional enzyme phosphoribosylanthranilate isomerase: indoleglycerolphosphate synthase from Escherichia coli refined at 2.0 A resolution.|
|Source||J. Mol. Biol. 223:477-507(1992).|