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PDBsum entry 2iv2
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Oxidoreductase
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PDB id
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2iv2
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References listed in PDB file
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Key reference
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Title
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Formate-Reduced e. Coli formate dehydrogenase h: the reinterpretation of the crystal structure suggests a new reaction mechanism.
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Authors
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H.C.Raaijmakers,
M.J.Romão.
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Ref.
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J Biol Inorg Chem, 2006,
11,
849-854.
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PubMed id
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Abstract
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Re-evaluation of the crystallographic data of the molybdenum-containing E. coli
formate dehydrogenase H (Boyington et al. Science 275:1305-1308, 1997), reported
in two redox states, reveals important structural differences for the
formate-reduced form, with large implications for the reaction mechanism
proposed in that work. We have re-refined the reduced structure with revised
protocols and found substantial rearrangement in some parts of it. The original
model is essentially correct but an important loop close to the molybdenum
active site was mistraced, and, therefore, catalytic relevant residues were
located in wrong positions. In particular selenocysteine-140, a ligand of
molybdenum in the original work, and essential for catalysis, is no longer bound
to the metal after reduction of the enzyme with formate. These results are
incompatible with the originally proposed reaction mechanism. On the basis of
our new interpretation, we have revised and proposed a new reaction mechanism,
which reconciles the new X-ray model with previous biochemical and extended
X-ray absorption fine structure data.
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Secondary reference #1
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Title
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Crystal structure of formate dehydrogenase h: catalysis involving mo, Molybdopterin, Selenocysteine, And an fe4s4 cluster.
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Authors
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J.C.Boyington,
V.N.Gladyshev,
S.V.Khangulov,
T.C.Stadtman,
P.D.Sun.
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Ref.
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Science, 1997,
275,
1305-1308.
[DOI no: ]
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PubMed id
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Figure 2.
Fig. 2. Schematic representation of the hydrogen-bonding
network coordinating MGD^801 and MGD^802. Residues are
color-coded according to sequence conservation^ among the known
sequences of MGD-containing FDH enzymes (11):^ magenta,
invariant; blue, well conserved; and green, not conserved.^ The
eight water molecules involved in hydrogen-bonding interactions^
are designated by orange circles. Hydrogen bonds present in the^
oxidized state, the reduced state, or both states are
represented^ by blue, red, or black dashed lines, respectively.
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Figure 5.
Fig. 5. The proposed reaction mechanism for FDH[H]. BV,
benzyl viologen.
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The above figures are
reproduced from the cited reference
with permission from the AAAs
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