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Literature summary for 5.1.3.2 extracted from

  • Beerens, K.; Soetaert, W.; Desmet, T.
    Characterization and mutational analysis of the UDP-Glc(NAc) 4-epimerase from Marinithermus hydrothermalis (2013), Appl. Microbiol. Biotechnol., 97, 7733-7740.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
gene galE, functional expression of N-termminally His6-tagged enzyme in Escherichia coli strain BL21(DE3) Marinithermus hydrothermalis

Protein Variants

Protein Variants Comment Organism
G118A/G119A site-directed mutagenesis, the mutant shows highly reduced activity with UDP-N-acetylglucosamine and reduced activity with UDP-Gal, the mutant's substrate specificity is shifted toward non-acetylated substrates Marinithermus hydrothermalis
G188S/G119S site-directed mutagenesis, the mutant shows highly reduced activity with UDP-N-acetylglucosamine and reduced activity with UDP-Gal, the mutant's substrate specificity is shifted toward non-acetylated substrates Marinithermus hydrothermalis
S116A site-directed mutagenesis, the mutant shows highly reduced activity with UDP-N-acetylglucosamine and reduced activity with UDP-Gal, the mutant's substrate specificity is shifted toward non-acetylated substrates Marinithermus hydrothermalis
S279Y site-directed mutagenesis, the mutant shows highly reduced activity with UDP-N-acetylglucosamine and reduced activity with UDP-Gal, the mutant's substrate specificity is shifted toward non-acetylated substrates Marinithermus hydrothermalis
T117S site-directed mutagenesis, the mutant shows highly reduced activity with UDP-N-acetylglucosamine and reduced activity with UDP-Gal, the mutant's substrate specificity is shifted toward non-acetylated substrates Marinithermus hydrothermalis

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.146
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, mutant G118S/G119S Marinithermus hydrothermalis
0.243
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, mutant G118A/G119A Marinithermus hydrothermalis
0.316
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, mutant S279Y Marinithermus hydrothermalis
0.362
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, wild-type enzyme Marinithermus hydrothermalis
0.426
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, mutant T117S Marinithermus hydrothermalis
0.437
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, mutant S116A Marinithermus hydrothermalis

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
UDP-N-acetyl-alpha-D-glucosamine Marinithermus hydrothermalis
-
UDP-N-acetyl-alpha-D-galactosamine
-
?

Organism

Organism UniProt Comment Textmining
Marinithermus hydrothermalis
-
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
additional information the enzyme is active on both acetylated and non-acetylated UDP-hexoses, see for EC 5.1.3.2 Marinithermus hydrothermalis ?
-
?
UDP-alpha-D-glucose
-
Marinithermus hydrothermalis UDP-alpha-D-galactose
-
?
UDP-N-acetyl-alpha-D-glucosamine
-
Marinithermus hydrothermalis UDP-N-acetyl-alpha-D-galactosamine
-
?

Subunits

Subunits Comment Organism
More sequence comparisons and structure homology modeling, overview. The enzyme's catalytic triad contains a threonine residue (Thr117) instead of the usual serine Marinithermus hydrothermalis

Synonyms

Synonyms Comment Organism
GalE
-
Marinithermus hydrothermalis
UDP-Glc(NAc) 4-epimerase
-
Marinithermus hydrothermalis

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
70
-
-
Marinithermus hydrothermalis

Temperature Stability [°C]

Temperature Stability Minimum [°C] Temperature Stability Maximum [°C] Comment Organism
45
-
half-life is 13.5 h Marinithermus hydrothermalis
60
-
half-life is 23 min Marinithermus hydrothermalis

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.37
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, mutant G118A/G119A Marinithermus hydrothermalis
0.78
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, mutant G118S/G119S Marinithermus hydrothermalis
0.99
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, mutant S279Y Marinithermus hydrothermalis
2.32
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, mutant S116A Marinithermus hydrothermalis
2.5
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, mutant T117S Marinithermus hydrothermalis
2.62
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, wild-type enzyme Marinithermus hydrothermalis

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7 7.5
-
Marinithermus hydrothermalis

pH Range

pH Minimum pH Maximum Comment Organism
6 9 over 50% of maximal activity at pH 6.0 and pH 9.0 Marinithermus hydrothermalis

General Information

General Information Comment Organism
evolution UDP-hexose 4-epimerases belong to the superfamily of short-chain dehydrogenase/reductase group 2, which typically show a two-domain structure Marinithermus hydrothermalis
additional information structure homology modeling, overview. The Marinithermus enzyme makes use of a TxnYx3K catalytic triad rather than the usual SxnYx3K triad. The enzyme's catalytic triad contains a threonine residue (Thr117) instead of the usual serine, the gatekeeper residue is responsible for the substrate specificity, the two consecutive glycine residues, Gly118 and Gly119, are a unique feature of GalE enzymes from Thermus species and important for activity as well as affinity Marinithermus hydrothermalis

kcat/KM [mM/s]

kcat/KM Value [1/mMs-1] kcat/KM Value Maximum [1/mMs-1] Substrate Comment Organism Structure
1.55
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, mutant G118A/G119A Marinithermus hydrothermalis
3.13
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, mutant S279Y Marinithermus hydrothermalis
5.39
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, mutant S116A Marinithermus hydrothermalis
5.43
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, mutant G118S/G119S Marinithermus hydrothermalis
5.92
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, mutant T117S Marinithermus hydrothermalis
6.61
-
UDP-N-acetyl-alpha-D-glucosamine pH 7.5, 45°C, wild-type enzyme Marinithermus hydrothermalis