CATH Classification

Domain Context

CATH Clusters

Superfamily Aldolase class I
Functional Family Regulatory protein TenI

Enzyme Information

2.5.1.3
Thiamine phosphate synthase.
based on mapping to UniProt P25053
(1) 4-amino-2-methyl-5-diphosphomethylpyrimidine + 2-((2R,5Z)-2-carboxy- 4-methylthiazol-5(2H)-ylidene)ethyl phosphate = diphosphate + thiamine phosphate + CO(2). (2) 4-amino-2-methyl-5-diphosphomethylpyrimidine + 2-(2-carboxy-4- methylthiazol-5-yl)ethyl phosphate = diphosphate + thiamine phosphate + CO(2). (3) 4-amino-2-methyl-5-diphosphomethylpyrimidine + 4-methyl-5- (2-phosphono-oxyethyl)thiazole = diphosphate + thiamine phosphate.
-!- The enzyme catalyzes the penultimate reaction in thiamine de novo biosynthesis, condensing the pyrimidine and thiazole components. -!- The enzyme is thought to accept the product of EC 2.8.1.10 as its substrate. -!- However, it has been shown that in some bacteria, such as Bacillus subtilis, an additional enzyme, EC 5.3.99.10 converts that compound into its tautomer 2-(2-carboxy-4-methylthiazol-5-yl)ethyl phosphate, and that it is the latter that serves as the substrate for the synthase. -!- In addition to this activity, the enzyme participates in a salvage pathway, acting on 4-methyl-5-(2-phosphono-oxyethyl)thiazole, which is produced from thiamine degradation products. -!- In yeast this activity is found in a bifunctional enzyme and in the plant Arabidopsis thaliana the activity is part of a trifunctional enzyme.
5.3.99.10
Thiazole tautomerase.
based on mapping to UniProt P25053
2-((2R,5Z)-2-carboxy-4-methylthiazol-5(2H)-ylidene)ethyl phosphate = 2-(2-carboxy-4-methylthiazol-5-yl)ethyl phosphate.
-!- The enzyme catalyzes the irreversible aromatization of the thiazole moiety of 2-((2R,5Z)-2-carboxy-4-methylthiazol-5(2H)-ylidene)ethyl phosphate.

UniProtKB Entries (1)

P25053
TENI_BACSU
Bacillus subtilis subsp. subtilis str. 168
Thiazole tautomerase

PDB Structure

PDB 1YAD
External Links
Method X-RAY DIFFRACTION
Organism Escherichia
Primary Citation
Structural characterization of the regulatory proteins TenA and TenI from Bacillus subtilis and identification of TenA as a thiaminase II.
Toms, A.V., Haas, A.L., Park, J.H., Begley, T.P., Ealick, S.E.
Biochemistry