| Type: | Conserved_site | Name: | Indole-3-glycerol phosphate synthase, conserved site |
| Description: | Indole-3-glycerol phosphate synthase () (IGPS) catalyses 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 catalyses N-(5'-phosphoribosyl)anthranilate isomerase () (PRAI) activity (see ), the third step of tryptophan biosynthesis. In fungi, IGPS is the central domain of a trifunctional enzyme that contains a PRAI C-terminal domain and a glutamine amidotransferase () (GATase) N-terminal domain (see ).A structure of the IGPS domain of the bifunctional enzyme from the mesophilic bacterium E. coli (eIGPS) has been compared with the monomeric indole-3-glycerol phosphatesynthase from the hyperthermophilic archaeon Sulfolobus solfataricus(sIGPS). Both are single-domain (beta/alpha)8 barrel proteins, with one (eIGPS) or two (sIGPS) additional helices inserted before the first beta strand []. This entry represents a highly conserved region within the N-terminal section of IGPS, which has been shown to be part of the active site cavity. | Short Name: | Indole-3-GlycerolPSynthase_CS |
