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PDBsum entry 2c29
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Oxidoreductase
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PDB id
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2c29
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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 grape dihydroflavonol 4-Reductase, A key enzyme in flavonoid biosynthesis.
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Authors
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P.Petit,
T.Granier,
B.L.D'Estaintot,
C.Manigand,
K.Bathany,
J.M.Schmitter,
V.Lauvergeat,
S.Hamdi,
B.Gallois.
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Ref.
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J Mol Biol, 2007,
368,
1345-1357.
[DOI no: ]
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PubMed id
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Abstract
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The nicotinamide adenine dinucleotide phosphate (NADPH)-dependent enzyme
dihydroflavonol 4-reductase (DFR) catalyzes a late step in the biosynthesis of
anthocyanins and condensed tannins, two flavonoid classes of importance to plant
survival and human nutrition. This enzyme has been widely investigated in many
plant species, but little is known about its structural and biochemical
properties. To provide a basis for detailed structure-function studies, the
crystal structure of Vitis vinifera DFR, heterologously expressed in Escherichia
coli, has been determined at 1.8 A resolution. The 3D structure of the ternary
complex obtained with the oxidized form of nicotinamide adenine dinucleotide
phosphate and dihydroquercetin, one of the DFR substrates, presents common
features with the short-chain dehydrogenase/reductase family, i.e., an
N-terminal domain adopting a Rossmann fold and a variable C-terminal domain,
which participates in substrate binding. The structure confirms the importance
of the 131-156 region, which lines the substrate binding site and enlightens the
role of a specific residue at position 133 (Asn or Asp), assumed to control
substrate recognition. The activity of the wild-type enzyme and its variant
N133D has been quantified in vitro, using dihydroquercetin or dihydrokaempferol.
Our results demonstrate that position 133 cannot be solely responsible for the
recognition of the B-ring hydroxylation pattern of dihydroflavonols.
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Figure 1.
Figure 1. Final steps of the flavonoid biosynthetic pathway
leading to the synthesis of anthocyanins and condensed tannins
(proanthocyanidins). DFR, dihydroflavonol 4-reductase; ANR,
anthocyanidin reductase; ANS, anthocyanidin synthase; LAR,
leucoanthocyanidin reductase; UFGT, 3-O-glycosyltransferase.
Figure 1. Final steps of the flavonoid biosynthetic pathway
leading to the synthesis of anthocyanins and condensed tannins
(proanthocyanidins). DFR, dihydroflavonol 4-reductase; ANR,
anthocyanidin reductase; ANS, anthocyanidin synthase; LAR,
leucoanthocyanidin reductase; UFGT, 3-O-glycosyltransferase.
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Figure 5.
Figure 5. (a) Geometry of the catalytic triad site. (b) Stereo
view of the catalytic site in the vicinity of the K167
side-chain. The lysine amino group interacts with a cluster of
five water molecules filling a hydrophilic cavity. (c) Stereo
view of the substrate binding site. DHQ is wrapped up by the N
and C-terminal parts of the protein: contacts are established
via hydrophilic interactions or hydrophobic residues of both N
and C-terminal domains. The color code is the same as in the
legend to Figure 4. Figure 5. (a) Geometry of the catalytic
triad site. (b) Stereo view of the catalytic site in the
vicinity of the K167 side-chain. The lysine amino group
interacts with a cluster of five water molecules filling a
hydrophilic cavity. (c) Stereo view of the substrate binding
site. DHQ is wrapped up by the N and C-terminal parts of the
protein: contacts are established via hydrophilic interactions
or hydrophobic residues of both N and C-terminal domains. The
color code is the same as in the legend to [3]Figure 4.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2007,
368,
1345-1357)
copyright 2007.
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