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PDBsum entry 4mj4
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Enzyme class:
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E.C.3.2.1.76
- L-iduronidase.
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Reaction:
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Hydrolysis of alpha-L-iduronosidic linkages in desulfated dermatan.
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DOI no:
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Nat Chem Biol
9:739-745
(2013)
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PubMed id:
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Insights into mucopolysaccharidosis I from the structure and action of α-L-iduronidase.
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H.Bie,
J.Yin,
X.He,
A.R.Kermode,
E.D.Goddard-Borger,
S.G.Withers,
M.N.James.
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ABSTRACT
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Mucopolysaccharidosis type I (MPS I), caused by mutations in the gene encoding
α-L-iduronidase (IDUA), is one of approximately 70 genetic disorders
collectively known as the lysosomal storage diseases. To gain insight into the
basis for MPS I, we crystallized human IDUA produced in an Arabidopsis thaliana
cgl mutant. IDUA consists of a TIM barrel domain containing the catalytic site,
a β-sandwich domain and a fibronectin-like domain. Structures of IDUA bound to
iduronate analogs illustrate the Michaelis complex and reveal a (2,5)B
conformation in the glycosyl-enzyme intermediate, which suggest a retaining
double displacement reaction involving the nucleophilic Glu299 and the general
acid/base Glu182. Unexpectedly, the N-glycan attached to Asn372 interacts with
iduronate analogs in the active site and is required for enzymatic activity.
Finally, these IDUA structures and biochemical analysis of the disease-relevant
P533R mutation have enabled us to correlate the effects of mutations in IDUA to
clinical phenotypes.
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');
}
}
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