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- **************************************************
- * Indole-3-glycerol phosphate synthase signature *
- **************************************************
-
- Indole-3-glycerol phosphate synthase (EC 4.1.1.48) (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 [1] have shown to be part of the active site cavity.
- We use this region as a signature pattern for IGPS.
-
- -Consensus pattern: [LIVMFY]-[LIVMC]-x-E-[LIVMFYC]-K-[KRSP]-[ATK]-S-P-[ST]-
- x(3)-[LIVMFYST]
- -Sequences known to belong to this class detected by the pattern: ALL, except
- for Phytophthora parasitica IGPS which lack this region.
- -Other sequence(s) detected in SWISS-PROT: NONE.
- -Last update: June 1994 / Pattern and text revised.
-
- [ 1] Wilmanns M., Priestle J.P., Niermann T., Jansonius J.N.
- J. Mol. Biol. 223:477-507(1992).
-