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PDBsum entry 1fdr
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References listed in PDB file
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Key reference
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Title
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The three-Dimensional structure of flavodoxin reductase from escherichia coli at 1.7 a resolution.
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Authors
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M.Ingelman,
V.Bianchi,
H.Eklund.
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Ref.
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J Mol Biol, 1997,
268,
147-157.
[DOI no: ]
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PubMed id
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Abstract
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Flavodoxin reductase from Escherichia coli is an FAD-containing oxidoreductase
that transports electrons between flavodoxin or ferredoxin and NADPH. Together
with flavodoxin, the enzyme is involved in the reductive activation of three E.
coli enzymes: cobalamin-dependent methionine synthase, pyruvate formate lyase
and anaerobic ribonucleotide reductase. An additional function for the
oxidoreductase appears to be to protect the bacteria against oxygen radicals.
The three-dimensional structure of flavodoxin reductase has been solved by
multiple isomorphous replacement, and has been refined at 1.7 A to an R-value of
18.4% and Rfree 24.8%. The monomeric molecule contains one beta-sandwich FAD
domain and an alpha/beta NADP domain. The overall structure is similar to other
reductases of the NADP-ferredoxin reductase family in spite of the low sequence
similarities within the family. Flavodoxin reductase lacks the loop which is
involved in the binding of the adenosine moiety of FAD in other FAD binding
enzymes of the superfamily but is missing in the FMN binding phthalate
dioxygenase reductase. Instead of this loop, the adenine interacts with an extra
tryptophan at the C terminus. The FAD in flavodoxin reductase has an unusual
bent conformation with a hydrogen bond between the adenine and the
isoalloxazine. This is probably the cause of the unusual spectrum of the enzyme.
There is a pronounced cleft close to the isoalloxazine that appears to be well
suited for binding of flavodoxin/ferredoxin. Two extra short strands of the
NADP-binding domain probably act as an anchor point for the binding of
flavodoxin.
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Figure 2.
Figure 2. Ribbon representation of the flavodoxin reductase
molecule made with the program MOLSCRIPT [Kraulis 1991]. The
secondary structure elements are labelled essentially as by
[Correll et al 1993]. Fβ1, 3–16; Fβ2, 17–26; Fβ3,
35–41; Fβ4, 48–54; Fβ5, 63–69; Fα1, 75–82; Fβ6,
85–92; 3[10], 99–103; Nβ1, 107–114; Nα1, 118–128;
3[10], 131–134; Nβ2, 135–144; Nα2, 151–163; Nβ3,
165–174; Nβ4, 181–183; Nα3a, 184–192; Nα3b, 192–200;
Nβ5, 206–213; Nα4, 214–230; βA, 232–236; βB,
237–241; Nβ6, 241–247. The FAD molecule is included as a
ball-and-stick model.
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Figure 7.
Figure 7. Stereo view surface representation of the
flavodoxin reductase made with the program GRASP [Nicholls et al
1993]. Positive potential is shown in blue and negative
potential in red. The FAD molecule is indicated in the middle.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(1997,
268,
147-157)
copyright 1997.
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