CATH Classification

Domain Context

CATH Clusters

Superfamily 3.40.50.880
Functional Family Imidazole glycerol phosphate synthase hisHF

Enzyme Information

4.3.2.10
Imidazole glycerol-phosphate synthase.
based on mapping to UniProt P33734
5-((5-phospho-1-deoxy-D-ribulos-1-ylamino)methylideneamino)-1-(5-phospho- beta-D-ribosyl)imidazole-4-carboxamide + L-glutamine = 5-amino-1- (5-phospho-beta-D-ribosyl)imidazole-4-carboxamide + D-erythro-1- (imidazol-4-yl)glycerol 3-phosphate + L-glutamate.
-!- The enzyme is involved in histidine biosynthesis, as well as purine nucleotide biosynthesis. -!- The enzymes from archaea and bacteria are heterodimeric. -!- A glutaminase component (cf. EC 3.5.1.2) produces an ammonia molecule that is transferred by a 25 A tunnel to a cyclase component, which adds it to the imidazole ring, leading to lysis of the molecule and cyclization of one of the products. -!- The glutminase subunit is only active within the dimeric complex. -!- In fungi and plants the two subunits are combined into a single polypeptide.
3.5.1.2
Glutaminase.
based on mapping to UniProt P33734
L-glutamine + H(2)O = L-glutamate + NH(3).

UniProtKB Entries (1)

P33734
HIS5_YEAST
Saccharomyces cerevisiae S288C
Imidazole glycerol phosphate synthase hisHF

PDB Structure

PDB 1OX4
External Links
Method X-RAY DIFFRACTION
Organism Escherichia
Primary Citation
Towards Understanding the Mechanism of the Complex Cyclization Reaction Catalyzed by Imidazole Glycerophosphate Synthase: Crystal Structures of a Ternary Complex and the Free Enzyme
Chaudhuri, B.N., Lange, C., Myers, R.S., Davisson, V.J., Smith, J.L.
Biochemistry