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PDBsum entry 2dc1
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Oxidoreductase
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PDB id
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2dc1
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References listed in PDB file
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Key reference
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Title
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Crystal structure of archaeal highly thermostable l-Aspartate dehydrogenase/NAD/citrate ternary complex.
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Authors
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K.Yoneda,
H.Sakuraba,
H.Tsuge,
N.Katunuma,
T.Ohshima.
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Ref.
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Febs J, 2007,
274,
4315-4325.
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PubMed id
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Abstract
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The crystal structure of the highly thermostable L-aspartate dehydrogenase
(L-aspDH; EC 1.4.1.21) from the hyperthermophilic archaeon Archaeoglobus
fulgidus was determined in the presence of NAD and a substrate analog, citrate.
The dimeric structure of A. fulgidus L-aspDH was refined at a resolution of 1.9
A with a crystallographic R-factor of 21.7% (R(free) = 22.6%). The structure
indicates that each subunit consists of two domains separated by a deep cleft
containing an active site. Structural comparison of the A. fulgidus
L-aspDH/NAD/citrate ternary complex and the Thermotoga maritima L-aspDH/NAD
binary complex showed that A. fulgidus L-aspDH assumes a closed conformation and
that a large movement of the two loops takes place during substrate binding.
Like T. maritima L-aspDH, the A. fulgidus enzyme is highly thermostable. But
whereas a large number of inter- and intrasubunit ion pairs are responsible for
the stability of A. fulgidus L-aspDH, a large number of inter- and intrasubunit
aromatic pairs stabilize the T. maritima enzyme. Thus stabilization of these two
L-aspDHs appears to be achieved in different ways. This is the first detailed
description of substrate and coenzyme binding to L-aspDH and of the molecular
basis of the high thermostability of a hyperthermophilic L-aspDH.
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