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PDBsum entry 1z2e
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Oxidoreductase
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PDB id
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1z2e
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References listed in PDB file
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Key reference
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Title
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Solution structures and backbone dynamics of arsenate reductase from bacillus subtilis: reversible conformational switch associated with arsenate reduction.
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Authors
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X.Guo,
Y.Li,
K.Peng,
Y.Hu,
C.Li,
B.Xia,
C.Jin.
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Ref.
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J Biol Chem, 2005,
280,
39601-39608.
[DOI no: ]
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PubMed id
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Abstract
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Arsenate reductase encoded by the chromosomal arsC gene in Bacillus subtilis
catalyzes the intracellular reduction of arsenate to arsenite, which is then
extruded from cells through an efficient and specific transport system. Herein,
we present the solution structures and backbone dynamics of both the reduced and
oxidized forms of arsenate reductase from B. subtilis. The overall structures of
both forms are similar to those of bovine low molecular weight protein-tyrosine
phosphatase and arsenate reductase from Staphylococcus aureus. However, several
features of the tertiary structure and mobility are notably different between
the reduced and oxidized forms of B. subtilis arsenate reductase, particularly
in the P-loop region and the segment Cys(82)-Cys(89). The backbone dynamics
results demonstrated that the reduced form of arsenate reductase undergoes
millisecond conformational changes in the functional P-loop and Cys(82)-Cys(89),
which may facilitate the formation of covalent intermediates and subsequent
reduction of arsenate. In the oxidized form, Cys(82)-Cys(89) shows motional
flexibility on both picosecond-to-nanosecond and possibly millisecond time
scales, which may facilitate the reduction of the oxidized enzyme by thioredoxin
to regenerate the active enzyme. Overall, the internal dynamics and static
structures of the enzyme provide insights into the molecular mechanism of
arsenate reduction, especially the reversible conformational switch and changes
in internal motions associated with the catalytic reaction.
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Figure 3.
FIGURE 3. Structural comparison. A, overlay of the C^  trace of
the solution structures of the reduced (red) and oxidized
(green) forms of B. subtilis ArsC; B, comparison of the local
structures of the P-loop of the reduced (left) and oxidized
(right) forms of ArsC; C, the C^ trace of reduced B.
subtilis ArsC in solution (red) superimposed with chain A of the
crystal structure (blue); D, the C^ trace of reduced B.
subtilis ArsC (red) superimposed with that of bovine low
molecular weight protein-tyrosine phosphatase (magenta); E, the
C^ trace of reduced B.
subtilis ArsC (red) superimposed with that of S. aureus ArsC
(cyan); F, the C^ trace of oxidized B.
subtilis ArsC (green) superimposed with that of S. aureus ArsC
(yellow).
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Figure 5.
FIGURE 5. Ribbon diagrams representing the dynamic
properties of B. subtilis ArsC. The ribbon diagrams of the
reduced (A) and oxidized (B) forms of B. subtilis ArsC represent
the internal motions on picosecond-to-nanosecond time scales,
with colors ranging from yellow to red and magenta corresponding
to  [e] values from 10 to 100
ps and >100 ps, respectively. The ribbon diagrams of the reduced
(C) and oxidized (D) forms of B. subtilis ArsC represent the
residues with conformational changes (R[ex] > 1 s-1) on the
millisecond time scale, colored in blue.
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2005,
280,
39601-39608)
copyright 2005.
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