EC Number   |
General Information |
Reference |
|---|
   5.1.3.31 | evolution |
analysis of molecular clusters of DTE gene sequences, phylogenetic analysis, overview |
-, 749220 |
| 5.1.3.31 | evolution |
the enzyme belongs to the D-tagatose 3-epimerase (D-TE) family |
-, 746850, 748592 |
| 5.1.3.31 | evolution |
the enzyme belongs to the D-tagatose 3-epimerase (D-TE) family enzymes. The overall fold of the subunit proves to be similar to those of the D-tagatose 3-epimerase from Pseudomonas cichorii and the D-psicose 3-epimerases from Agrobacterium tumefaciens and Clostridium cellulolyticum. But the situation at the subunit-subunit interface differs substantially from that in D-tagatose 3-epimerase family enzymes. In MJ1311p, Glu125, Leu126 and Trp127 from one subunit are located over the metal-ion-binding site of the other subunit and contribute to the active site, narrowing the substrate-binding cleft. Moreover, the nine residues comprising a trinuclear zinc centre in endonuclease IV are strictly conserved in MJ1311p, although a distinct groove involved in DNA binding is not present. The active-site architecture of MJ1311p is quite unique and is substantially different from those of D-tagatose 3-epimerase family enzymes and endonuclease IV |
-, 746648 |
| 5.1.3.31 | more |
the hydrophobic groove that acts as an accessible surface for substrate binding is formed through the dimerization of PcDTE. The sugar-ring opening of a substrate may occur in the hydrophobic groove and also that the narrow channel of the passageway to the catalytic site allows a substrate in the linear form to pass through. Ligand-binding structure at the catalytic site, overview |
746850 |
| 5.1.3.31 | more |
the O1 of substrate D-fructose forms hydrogen bonds with His192 and Glu162 to help the correct metal coordination of the substrate. The O2 forms hydrogen bonds with His192 and Arg221. Glu156 forms hydrogen bonds with O3, and Glu250 directs its OE2 atom to a hydrogen atom attached to C3. Because D-fructose has the same configurations of C1, C2 and C3 as D-tagatose, the interactions between D-fructose at the 1-, 2- and 3-positions and the enzyme are very similar to those in other DTE/DPE family enzymes. Residue R118 forms a hydrogen bond with O4 of D-fructose and may regulate the substrate specificity. The strengthened hydrophobic interaction may attribute to the recognition of D-tagatose, D-psicose, and D-sorbose. Enzyme homology modeling and structure comparisons, overview |
-, 748592 |
| 5.1.3.31 | physiological function |
D-tagatose 3-epimerase (DTE) catalyzes epimerization between D-tagatose and D-sorbose. DTE from Pseudomonas cichorii (PcDTE) has a broad substrate specificity and efficiently catalyzes the epimerization of not only D-tagatose to D-sorbose but also D-fructose to D-psicose (D-allulose) |
746850 |
| 5.1.3.31 | physiological function |
the purified D-tagatose 3-epimerase from Rhodobacter sphaeroides catalyzes the epimerization of D-fructose to D-psicose at the C3 position |
-, 748592 |
