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PDBsum entry 1ipd
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Oxidoreductase
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PDB id
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1ipd
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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 of a highly thermostable enzyme, 3-Isopropylmalate dehydrogenase of thermus thermophilus at 2.2 a resolution.
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Authors
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K.Imada,
M.Sato,
N.Tanaka,
Y.Katsube,
Y.Matsuura,
T.Oshima.
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Ref.
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J Mol Biol, 1991,
222,
725-738.
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PubMed id
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Abstract
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The three-dimensional structure of the highly thermostable 3-isopropylmalate
dehydrogenase (IPMDH) from Thermus thermophilus has been determined by the
multiple isomorphous replacement method and refined to 2.2 A resolution. The
final R-factor is 0.185 for 20,307 reflections. The crystal asymmetric unit has
one subunit consisting of 345 amino acid residues. The polypeptide chain of this
subunit is folded into two domains (first and second domains) with parallel
alpha/beta motifs. The domains are similar in their conformations and folding
topologies, but differ from those of the NAD-binding domains of such well-known
enzymes as the alcohol and lactate dehydrogenases. A beta-strand that is a part
of the long arm-like polypeptide protruding from the second domain comes into
contact with another subunit and contributes to the formation of an isologous
dimer with a crystallographic 2-fold symmetry. Close subunit contacts are also
present at two alpha-helices in the second domain. These helices strongly
interact hydrophobically with the corresponding helices of the other subunit to
form a hydrophobic core at the center of the dimer. Two large pockets that exist
between the first domain of one subunit and the second domain of the other
include the amino acid residues responsible for substrate binding. These results
indicate that the dimeric form is essential for the IPMDH to express enzymatic
activity and that the close subunit contact at the hydrophobic core is important
for the thermal stability of the enzyme.
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Secondary reference #1
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Title
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Purification, Catalytic properties, And thermal stability of threo-Ds-3-Isopropylmalate dehydrogenase coded by leub gene from an extreme thermophile, Thermus thermophilus strain hb8.
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Authors
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T.Yamada,
N.Akutsu,
K.Miyazaki,
K.Kakinuma,
M.Yoshida,
T.Oshima.
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Ref.
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J Biochem (tokyo), 1990,
108,
449-456.
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PubMed id
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Secondary reference #2
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Title
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Crystallization and preliminary X-Ray data for 3-Isopropylmalate dehydrogenase of thermus thermophilus.
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Authors
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Y.Katsube,
N.Tanaka,
A.Takenaka,
T.Yamada,
T.Oshima.
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Ref.
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J Biochem (tokyo), 1988,
104,
679-680.
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PubMed id
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