CATH Classification

Domain Context

CATH Clusters

Superfamily 3.40.50.880
Functional Family

Enzyme Information

4.3.2.10
Imidazole glycerol-phosphate synthase.
based on mapping to UniProt Q7SIC0
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 Q7SIC0
L-glutamine + H(2)O = L-glutamate + NH(3).

UniProtKB Entries (1)

Q7SIB9
HIS6_THET8
Thermus thermophilus HB8
Imidazole glycerol phosphate synthase subunit HisF

PDB Structure

PDB 1KA9
External Links
Method X-RAY DIFFRACTION
Organism Escherichia
Primary Citation
Structure of imidazole glycerol phosphate synthase from Thermus thermophilus HB8: open-closed conformational change and ammonia tunneling.
Omi, R., Mizuguchi, H., Goto, M., Miyahara, I., Hayashi, H., Kagamiyama, H., Hirotsu, K.
J.Biochem.