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PDBsum entry 2wdf
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References listed in PDB file
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Key reference
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Title
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Mechanism for the hydrolysis of a sulfur-Sulfur bond based on the crystal structure of the thiosulfohydrolase soxb.
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Authors
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V.Sauvé,
P.Roversi,
K.J.Leath,
E.F.Garman,
R.Antrobus,
S.M.Lea,
B.C.Berks.
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Ref.
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J Biol Chem, 2009,
284,
21707-21718.
[DOI no: ]
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PubMed id
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Abstract
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SoxB is an essential component of the bacterial Sox sulfur oxidation pathway.
SoxB contains a di-manganese(II) site and is proposed to catalyze the release of
sulfate from a protein-bound cysteine S-thiosulfonate. A direct assay for SoxB
activity is described. The structure of recombinant Thermus thermophilus SoxB
was determined by x-ray crystallography to a resolution of 1.5 A. Structures
were also determined for SoxB in complex with the substrate analogue thiosulfate
and in complex with the product sulfate. A mechanistic model for SoxB is
proposed based on these structures.
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Figure 2.
Structure of T. thermophilus SoxB and the effect of binding
the substrate analogue thiosulfate.A, cartoon representation of
the overall structure of SoxB using the SoxB-glycerol
coordinates. The N-terminal domain is shown in blue with the
N-terminal loop subdomain in green. The interdomain helix is
shown in yellow, the C-terminal domain is in red, and the
manganese ions are in purple. The route of access to the active
site is indicated with an arrow. B, a representation of the
residues that are critical for the relative orientation of the
substrate analogue thiosulfate and the reactive bridging
hydroxide ion based on the SoxB-Mn^2+-thiosulfate structure. The
manganese ions are in purple, and the oxygen of the reactive
bridging hydroxide is in red. Thiosulfate is shown in stick
representation. The footprint of the thiosulfate S–S bond on
the protein surface is green. Distances between selected atoms
(indicated by dashed lines) are given. C, the two conformations
of loop 465–476. The closed conformation observed when the
active site is empty (SoxB-Mn^2+ structure) is shown in yellow,
and the open conformation adopted upon binding of the substrate
analogue thiosulfate at the active site (SoxB-Mn^2+-thiosulfate
structure) is in red. The manganese ions are shown in purple,
and the thiosulfate molecule present in the open conformation in
a stick representation.
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Figure 5.
Proposed mechanism for SoxB. The three steps of the cycle
depicted here are based on the SoxB-Mn^2+,
SoxB-Mn^2+-thiosulfate, and SoxB-Mn^2+-sulfate (conformer 2)
structures.
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2009,
284,
21707-21718)
copyright 2009.
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