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PDBsum entry 1j0h
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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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Three-Dimensional structure and substrate binding of bacillus stearothermophilus neopullulanase.
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Authors
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H.Hondoh,
T.Kuriki,
Y.Matsuura.
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Ref.
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J Mol Biol, 2003,
326,
177-188.
[DOI no: ]
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PubMed id
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Abstract
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Crystal structures of Bacillus stearothermophilus TRS40 neopullulanase and its
complexes with panose, maltotetraose and isopanose were determined at
resolutions of 1.9, 2.4, 2.8 and 3.2A, respectively. Since the latter two
carbohydrates are substrates of this enzyme, a deactivated mutant at the
catalytic residue Glu357-->Gln was used for complex crystallization. The
structures were refined at accuracies with r.m.s. deviations of bond lengths and
bond angles ranging from 0.005A to 0.008A and 1.3 degrees to 1.4 degrees,
respectively. The active enzyme forms a dimer in the crystalline state and in
solution. The monomer enzyme is composed of four domains, N, A, B and C, and has
a (beta/alpha)(8)-barrel in domain A. The active site lies between domain A and
domain N from the other monomer. The results show that dimer formation makes the
active-site cleft narrower than those of ordinary alpha-amylases, which may
contribute to the unique substrate specificity of this enzyme toward both
alpha-1,4 and alpha-1,6-glucosidic linkages. This specificity may be influenced
by the subsite structure. Only subsites -1 and -2 are commonly occupied by the
product and substrates, suggesting that equivocal recognition occurs at the
other subsites, which contributes to the wide substrate specificity of this
enzyme.
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Figure 1.
Figure 1. (a) Monomer structure of neopullulanase
with domain names. Three catalytic residues, Asp328,
Glu357 and Asp424, are shown as ball-and-stick models
and a bound calcium ion is shown as an orange sphere.
(b) Dimer structure of neopullulanase. Mol-1 and Mol-2
are colored green and red, respectively. Bound panose
molecules at the active cleft are shown to indicate the
location of the active site. The Figure was produced
with MOLSCRIPT
34
and RENDER from the Raster3D
package.
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Figure 6.
Figure 6. Stereo views of the active cleft of the enzyme with bound substrates: panose (green), maltotetraose (blue)
and isopanose (red). Hydrophobic residues are shown in yellow.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2003,
326,
177-188)
copyright 2003.
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Secondary reference #1
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Title
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Action of neopullulanase. Neopullulanase catalyzes both hydrolysis and transglycosylation at alpha-(1----4)- And alpha-(1----6)-Glucosidic linkages.
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Authors
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H.Takata,
T.Kuriki,
S.Okada,
Y.Takesada,
M.Iizuka,
N.Minamiura,
T.Imanaka.
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Ref.
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J Biol Chem, 1992,
267,
18447-18452.
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PubMed id
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Secondary reference #2
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Title
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Pattern of action of bacillus stearothermophilus neopullulanase on pullulan.
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Authors
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T.Imanaka,
T.Kuriki.
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Ref.
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J Bacteriol, 1989,
171,
369-374.
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PubMed id
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Secondary reference #3
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Title
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New type of pullulanase from bacillus stearothermophilus and molecular cloning and expression of the gene in bacillus subtilis.
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Authors
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T.Kuriki,
S.Okada,
T.Imanaka.
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Ref.
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J Bacteriol, 1988,
170,
1554-1559.
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PubMed id
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