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Literature summary for 5.4.99.9 extracted from

  • Pierdominici-Sottile, G.; Cossio-Perez, R.; Da Fonseca, I.; Kizjakina, K.; Tanner, J.J.; Sobrado, P.
    Steric control of the rate-limiting step of UDP-galactopyranose mutase (2018), Biochemistry, 57, 3713-3721 .
    View publication on PubMedView publication on EuropePMC
Search for more literature for 5.4.99.9

Protein Variants

Protein Variants Comment Organism
W315A site-directed mutagenesis, the mutant shows reduced activity compared to the wild-type enzyme. The extra space afforded by the absence of the Trp315 wall possibly lowers the free energy barrier of the cyclization step of the catalytic mechanism, allowing product release to become rate-limiting Aspergillus fumigatus

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
-
 additional information Michaelis-Menten kinetics and kinetic solvent viscosity effects with wild-type and mutant enzymes. A strong dependence of the kcat value on solution viscosity is observed when UDP-beta-L-arabinofuranose is used as the substrate with the wild-type enzyme Aspergillus fumigatus
0.094
-
 UDP-beta-L-arabinofuranose pH 7.0, 37°C, recombinant wild-type enzyme Aspergillus fumigatus
0.193
-
 UDP-alpha-D-galactofuranose pH 7.0, 37°C, recombinant mutant W315A Aspergillus fumigatus
0.45
-
 UDP-alpha-D-galactofuranose pH 7.0, 37°C, recombinant wild-type enzyme Aspergillus fumigatus
0.7
-
 UDP-beta-L-arabinofuranose pH 7.0, 37°C, recombinant mutant W315A Aspergillus fumigatus

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
UDP-alpha-D-galactopyranose Aspergillus fumigatus
-
 UDP-alpha-D-galactofuranose
-
 r

Organism

Organism UniProt Comment Textmining
Aspergillus fumigatus Q4W1X2 i.e. Neosartorya fumigata
-

Reaction

Reaction Comment Organism Reaction ID
UDP-alpha-D-galactopyranose = UDP-alpha-D-galactofuranose catalytic reaction mechanism, detailed overview. A covalent adduct is formed between the substrate and the FADH cofactor, temporarily breaking the glycosidic bond, followed by an internal proton transfer between N5FADH and O6FADH. The next step involves linearization of the sugar and formation of the iminium ion species. In the next step, the sugar cyclizes into its five-membered ring form. This step is isotope sensitive and is considered to be the chemical rate-limiting step of the mechanism. Once the furanose form of the sugar is reached, another internal proton transfer takes place, and the glycosidic bond to UDP is formed. Finally, the product of the reaction exits the active site of the enzyme Aspergillus fumigatus
a

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
UDP-alpha-D-galactofuranose
-
 Aspergillus fumigatus UDP-alpha-D-galactopyranose
-
 r
UDP-alpha-D-galactopyranose
-
 Aspergillus fumigatus UDP-alpha-D-galactofuranose
-
 r
UDP-beta-L-arabinofuranose
-
 Aspergillus fumigatus UDP-beta-L-arabinopyranose
-
 r
UDP-beta-L-arabinopyranose
-
 Aspergillus fumigatus UDP-beta-L-arabinofuranose
-
 r

Synonyms

Synonyms Comment Organism
AfUGM
-
 Aspergillus fumigatus
glfA
-
 Aspergillus fumigatus
UGM
-
 Aspergillus fumigatus

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
37
-
 assay at Aspergillus fumigatus

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.14
-
 UDP-beta-L-arabinofuranose pH 7.0, 37°C, recombinant wild-type enzyme Aspergillus fumigatus
0.23
-
 UDP-beta-L-arabinofuranose pH 7.0, 37°C, recombinant mutant W315A Aspergillus fumigatus
0.27
-
 UDP-alpha-D-galactofuranose pH 7.0, 37°C, recombinant mutant W315A Aspergillus fumigatus
100
-
 UDP-alpha-D-galactofuranose pH 7.0, 37°C, recombinant wild-type enzyme Aspergillus fumigatus

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7
-
 assay at Aspergillus fumigatus

Cofactor

Cofactor Comment Organism Structure
FAD a flavoenzyme, FAD is tightly bound, binding kinetics and mechanism Aspergillus fumigatus

General Information

General Information Comment Organism
additional information molecular dynamics simulations. Binding modes of substrates in the active site of enzyme AfUGM Aspergillus fumigatus
physiological function galactofuranose (Galf) biosynthesis begins with the conversion of UDP-galactopyranose (UDP-Galp) to UDP-Galf as a rate-limiting step catalyzed by the flavoenzyme UDP-galactopyranose mutase (UGM). Enzyme UGM is essential for the survival and proliferation of several pathogens. UGM from the pathogenic fungus Aspergillus fumigatus also catalyzes the isomerization of UDP-arabinopyranose (UDP-Arap), which differs from UDPGalp by lacking a -CH2-OH substituent at the C5 position of the hexose ring Aspergillus fumigatus

kcat/KM [mM/s]

kcat/KM Value [1/mMs-1] kcat/KM Value Maximum [1/mMs-1] Substrate Comment Organism Structure
0.33
-
 UDP-beta-L-arabinofuranose pH 7.0, 37°C, recombinant mutant W315A Aspergillus fumigatus
1.4
-
 UDP-alpha-D-galactofuranose pH 7.0, 37°C, recombinant mutant W315A Aspergillus fumigatus
1.489
-
 UDP-beta-L-arabinofuranose pH 7.0, 37°C, recombinant wild-type enzyme Aspergillus fumigatus
222.22
-
 UDP-alpha-D-galactofuranose pH 7.0, 37°C, recombinant wild-type enzyme Aspergillus fumigatus