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PDBsum entry 1kxh
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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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Crystallographic evidence of a transglycosylation reaction: ternary complexes of a psychrophilic alpha-Amylase.
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Authors
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N.Aghajari,
M.Roth,
R.Haser.
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Ref.
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Biochemistry, 2002,
41,
4273-4280.
[DOI no: ]
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PubMed id
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Abstract
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The psychrophilic Pseudoalteromonas haloplanctis alpha-amylase is shown to form
ternary complexes with two alpha-amylase inhibitors present in the active site
region, namely, a molecule of Tris and a trisaccharide inhibitor or
heptasaccharide inhibitor, respectively. The crystal structures of these
complexes have been determined by X-ray crystallography to 1.80 and 1.74 A
resolution, respectively. In both cases, the prebound inhibitor Tris is expelled
from the active site by the incoming oligosaccharide inhibitor substrate
analogue, but stays linked to it, forming well-defined ternary complexes with
the enzyme. These results illustrate competition in the crystalline state
between two inhibitors, an oligosaccharide substrate analogue and a Tris
molecule, bound at the same time in the active site region. Taken together,
these structures show that the enzyme performs transglycosylation in the complex
with the pseudotetrasaccharide acarbose (confirmed by a mutant structure),
leading to a well-defined heptasaccharide, considered as a more potent
inhibitor. Furthermore, the substrate-induced ordering of water molecules within
a channel highlights a possible pathway used for hydrolysis of starch and
related poly- and oligosaccharides.
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Secondary reference #1
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Title
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Structures of the psychrophilic alteromonas haloplanctis alpha-Amylase give insights into cold adaptation at a molecular level.
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Authors
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N.Aghajari,
G.Feller,
C.Gerday,
R.Haser.
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Ref.
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Structure, 1998,
6,
1503-1516.
[DOI no: ]
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PubMed id
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Figure 4.
Figure 4. A representation of charges at the surfaces of
(a) AHA, (b) HPA and (c) BLA, displayed at the same potential
range. Color codes are: red, aspartic and glutamic acids; blue,
lysines and arginines. This figure was generated with the
program GRASP [57].
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The above figure is
reproduced from the cited reference
with permission from Cell Press
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Secondary reference #2
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Title
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Crystal structures of the psychrophilic alpha-Amylase from alteromonas haloplanctis in its native form and complexed with an inhibitor.
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Authors
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N.Aghajari,
G.Feller,
C.Gerday,
R.Haser.
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Ref.
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Protein Sci, 1998,
7,
564-572.
[DOI no: ]
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PubMed id
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