3.6.1.57: UDP-2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose hydrolase
This is an abbreviated version!
For detailed information about UDP-2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose hydrolase, go to the full flat file.
Reaction
Synonyms
Cj1312, PseG, UDP-6-deoxy-AltdiNAc hydrolase, UDP-sugar hydrolase
ECTree
3.6.1.57 UDP-2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose hydrolaseAdvanced search results
results (
results (Substrates Products
Substrates Products on EC 3.6.1.57 - UDP-2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose hydrolase
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SUBSTRATE 
PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
UDP-2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose + H2O
2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose + UDP
additional information
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molecular modeling identifies a His17-coordinated water molecule as the putative nucleophile and suggests the UDP-sugar substrate adopts a twist-boat conformation upon binding to PseG, enhancing the exposure of the anomeric bond cleaved and favoring inversion at C1
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UDP-2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose + H2O
2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose + UDP
the enzyme is involved in biosynthesis of pseudaminic acid (i.e. 5,7-diacetamido-3,5,7,9-tetradeoxy-L-glycero-alpha-L-manno-nonulosonic acid). Flagella of Campylobacter jejuni are important virulence determinants, whose proper assembly and function are dependent upon glycosylation at multiple positions by sialic acid-like sugars, such as 5,7-diacetamido-3,5,7,9-tetradeoxy-L-glycero-L-manno-nonulosonic acid (pseudaminic acid)
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UDP-2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose + H2O
2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose + UDP
the enzyme is involved in biosynthesis of pseudaminic acid (i.e. 5,7-diacetamido-3,5,7,9-tetradeoxy-L-glycero-alpha-L-manno-nonulosonic acid). The large value of the specificity constant suggests that hydrolysis of UDP-2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose is the biologically relevant reaction catalyzed by this enzyme
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UDP-2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose + H2O
2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose + UDP
catalyzes the reaction via a C-O bond cleavage mechanism with inversion of stereochemistry at C-1. No detectable activity with UDP-GlcNAc and an extremely low level of activity (less than 1%) with the biosynthetic precursor, UDP-4-amino-2,4,6-trideoxy-beta-L-AltNAc, indicating that the enzyme exhibits substrate specificity. A solvent derived oxygen atom is incorporated into the sugar during hydrolysis and is consistent with a C-O bond cleavage mechanism in which water directly attacks the anomeric carbon to displace UDP
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UDP-2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose + H2O
2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose + UDP
His17 functions as an active site base, thereby activating the nucleophilic water molecule for attack of the anomeric C-O bond of the UDP-sugar. No activity was observed with UDP-4-amino-4,6-dideoxy-beta-L-AltNAc or UDP-2,4-diacetamido-2,4,6-trideoxy-alpha-D-glucopyranose or UDP-2,4-diacetamido-bacillosamine
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UDP-2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose + H2O
2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose + UDP
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UDP-2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose + H2O
2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose + UDP
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