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Information on EC 5.1.3.24 - N-acetylneuraminate epimerase and Organism(s) Escherichia coli and UniProt Accession P39371

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EC Tree
     5 Isomerases
         5.1 Racemases and epimerases
             5.1.3 Acting on carbohydrates and derivatives
                5.1.3.24 N-acetylneuraminate epimerase
IUBMB Comments
Sialoglycoconjugates present in vertebrates are linked exclusively by alpha-linkages and are released in alpha form during degradation. This enzyme accelerates maturotation to the beta form via the open form (which also occurs as a slow spontaneous reaction). The open form is necessary for further metabolism by the bacteria.
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This record set is specific for:
Escherichia coli
UNIPROT: P39371
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The taxonomic range for the selected organisms is: Escherichia coli
The enzyme appears in selected viruses and cellular organisms
Reaction Schemes
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Synonyms
N-acetylneuraminate mutarotase, sialic acid epimerase, YjhT, more
SYNONYM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
N-acetylneuraminate mutarotase
-
sialic acid epimerase
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N-acetylneuraminate mutarotase
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-
-
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sialic acid epimerase
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-
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YjhT
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-
-
-
SYSTEMATIC NAME
IUBMB Comments
N-acetyl-alpha-neuraminate 2-epimerase
Sialoglycoconjugates present in vertebrates are linked exclusively by alpha-linkages and are released in alpha form during degradation. This enzyme accelerates maturotation to the beta form via the open form (which also occurs as a slow spontaneous reaction). The open form is necessary for further metabolism by the bacteria.
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
N-acetyl-alpha-neuraminate
N-acetyl-beta-neuraminate
show the reaction diagram
NATURAL SUBSTRATE
NATURAL PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
N-acetyl-alpha-neuraminate
N-acetyl-beta-neuraminate
show the reaction diagram
probably facilitates sialidase-negative bacteria to compete sucessfully for limited amounts of extracellular Neu5Ac, which is likely taken up in he beta-anomer. In addition, the rapid removal of sialic acid from solution might be advantageous to the bacterium to damp down host responses
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-
?
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
-
SwissProt
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
physiological function
probably facilitates sialidase-negative bacteria to compete sucessfully for limited amounts of extracellular Neu5Ac, which is likely taken up in he beta-anomer. In addition, the rapid removal of sialic acid from solution might be advantageous to the bacterium to damp down host responses
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
38685
2 * 38685, electrospray mass spectrometry
73900
equilibrium sedimentation
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
dimer
2 * 38685, electrospray mass spectrometry
CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
vapor diffusion method, 1.5 A resolution
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
E209A
the mutant of YjhT is severely impaired in its ability to enhance the mutarotation rate above the spontaneous rate. Circular dichroism spectrum of the mutant is indistinguishable from that of the wild-type protein, suggesting that the phenotype is not because of misfolding of YjhT
E325A
mutation has no effect on the activity
H278A
mutation has no effect on the activity
K11A
mutation has no effect on the activity
K283A
mutation has no effect on the activity
R215A
mutant shows a decreased but observable activity. Circular dichroism spectrum of the mutant is indistinguishable from that of the wild-type protein, suggesting that the phenotype is not because of misfolding of YjhT
Y309A
mutation has no effect on the activity
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
expression in Escherichia coli
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Severi, E.; Mller, A.; Potts, J.R.; Leech, A.; Williamson, D.; Wilson, K.S.; Thomas, G.H.
Sialic acid mutarotation is catalyzed by the Escherichia coli beta-propeller protein YjhT
J. Biol. Chem.
283
4841-4849
2008
Escherichia coli (P39371)
Manually annotated by BRENDA team