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| - | [[Image:2dtd.gif|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_2dtd| PDB=2dtd | SCENE= }} | | {{STRUCTURE_2dtd| PDB=2dtd | SCENE= }} |
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| - | '''Structure of Thermoplasma acidophilum aldohexose dehydrogenase (AldT) in ligand-free form'''
| + | ===Structure of Thermoplasma acidophilum aldohexose dehydrogenase (AldT) in ligand-free form=== |
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| - | ==Overview==
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| - | The D-aldohexose dehydrogenase from the thermoacidophilic archaea Thermoplasma acidophilum (AldT) belongs to the short-chain dehydrogenase/reductase (SDR) superfamily and catalyzes the oxidation of several monosaccharides with a preference for NAD(+) rather than NADP(+) as a cofactor. It has been found that AldT is a unique enzyme that exhibits the highest dehydrogenase activity against D-mannose. Here, we describe the crystal structures of AldT in ligand-free form, in complex with NADH, and in complex with the substrate D-mannose, at 2.1 A, 1.65 A, and 1.6 A resolution, respectively. The AldT subunit forms a typical SDR fold with an unexpectedly long C-terminal tail and assembles into an intertwined tetramer. The D-mannose complex structure reveals that Glu84 interacts with the axial C2 hydroxyl group of the bound D-mannose. Structural comparison with Bacillus megaterium glucose dehydrogenase (BmGlcDH) suggests that the conformation of the glutamate side-chain is crucial for discrimination between D-mannose and its C2 epimer D-glucose, and the conformation of the glutamate side-chain depends on the spatial arrangement of nearby hydrophobic residues that do not directly interact with the substrate. Elucidation of the D-mannose recognition mechanism of AldT further provides structural insights into the unique substrate selectivity of AldT. Finally, we show that the extended C-terminal tail completely shuts the substrate-binding pocket of the neighboring subunit both in the presence and absence of substrate. The elaborate inter-subunit interactions between the C-terminal tail and the entrance of the substrate-binding pocket imply that the tail may play a pivotal role in the enzyme activity. | + | The line below this paragraph, {{ABSTRACT_PUBMED_17300803}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 17300803 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_17300803}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Yasutake, Y.]] | | [[Category: Yasutake, Y.]] |
| | [[Category: Rossmann fold]] | | [[Category: Rossmann fold]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 01:19:22 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 15:48:46 2008'' |
Revision as of 12:48, 29 July 2008
Template:STRUCTURE 2dtd
Structure of Thermoplasma acidophilum aldohexose dehydrogenase (AldT) in ligand-free form
Template:ABSTRACT PUBMED 17300803
About this Structure
2DTD is a Single protein structure of sequence from Thermoplasma acidophilum. Full crystallographic information is available from OCA.
Reference
Structural insights into unique substrate selectivity of Thermoplasma acidophilum D-aldohexose dehydrogenase., Yasutake Y, Nishiya Y, Tamura N, Tamura T, J Mol Biol. 2007 Apr 6;367(4):1034-46. Epub 2007 Jan 16. PMID:17300803
Page seeded by OCA on Tue Jul 29 15:48:46 2008
