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PDBsum entry 1knp
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Oxidoreductase
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PDB id
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1knp
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Structure of FAD-Bound l-Aspartate oxidase: insight into substrate specificity and catalysis.
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Authors
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R.T.Bossi,
A.Negri,
G.Tedeschi,
A.Mattevi.
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Ref.
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Biochemistry, 2002,
41,
3018-3024.
[DOI no: ]
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PubMed id
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Abstract
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L-Aspartate oxidase (Laspo) catalyzes the conversion of L-Asp to iminoaspartate,
the first step in the de novo biosynthesis of NAD(+). This bacterial pathway
represents a potential drug target since it is absent in mammals. The Laspo
R386L mutant was crystallized in the FAD-bound catalytically competent form and
its three-dimensional structure determined at 2.5 A resolution in both the
native state and in complex with succinate. Comparison of the R386L holoprotein
with the wild-type apoenzyme [Mattevi, A., Tedeschi, G., Bacchella, L., Coda,
A., Negri, A., and Ronchi, S. (1999) Structure 7, 745-756] reveals that cofactor
incorporation leads to the ordering of two polypeptide segments (residues 44-53
and 104-141) and to a 27 degree rotation of the capping domain. This motion
results in the formation of the active site cavity, located at the interface
between the capping domain and the FAD-binding domain. The structure of the
succinate complex indicates that the cavity surface is decorated by two clusters
of H-bond donors that anchor the ligand carboxylates. Moreover, Glu121, which is
strictly conserved among Laspo sequences, is positioned to interact with the
L-Asp alpha-amino group. The architecture of the active site of the Laspo
holoenzyme is remarkably similar to that of respiratory fumarate reductases,
providing strong evidence for a common mechanism of catalysis in Laspo and
flavoproteins of the succinate dehydrogenase/fumarate reductase family. This
implies that Laspo is mechanistically distinct from other flavin-dependent amino
acid oxidases, such as the prototypical D-amino acid oxidase.
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