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PDBsum entry 1a2m
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Oxidoreductase
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PDB id
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1a2m
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Contents |
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* Residue conservation analysis
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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 structures of reduced and oxidized dsba: investigation of domain motion and thiolate stabilization.
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Authors
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L.W.Guddat,
J.C.Bardwell,
J.L.Martin.
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Ref.
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Structure, 1998,
6,
757-767.
[DOI no: ]
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PubMed id
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Abstract
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BACKGROUND: The redox proteins that incorporate a thioredoxin fold have diverse
properties and functions. The bacterial protein-folding factor DsbA is the most
oxidizing of the thioredoxin family. DsbA catalyzes disulfide-bond formation
during the folding of secreted proteins. The extremely oxidizing nature of DsbA
has been proposed to result from either domain motion or stabilizing active-site
interactions in the reduced form. In the domain motion model, hinge bending
between the two domains of DsbA occurs as a result of redox-related
conformational changes. RESULTS: We have determined the crystal structures of
reduced and oxidized DsbA in the same crystal form and at the same pH (5.6). The
crystal structure of a lower pH form of oxidized DsbA has also been determined
(pH 5.0). These new crystal structures of DsbA, and the previously determined
structure of oxidized DsbA at pH 6.5, provide the foundation for analysis of
structural changes that occur upon reduction of the active-site disulfide bond.
CONCLUSIONS: The structures of reduced and oxidized DsbA reveal that hinge
bending motions do occur between the two domains. These motions are independent
of redox state, however, and therefore do not contribute to the energetic
differences between the two redox states. Instead, the observed domain motion is
proposed to be a consequence of substrate binding. Furthermore, DsbA's highly
oxidizing nature is a result of hydrogen bond, electrostatic and helix-dipole
interactions that favour the thiolate over the disulfide at the active site.
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Figure 4.
Figure 4. Symmetry-related contact in the OX2 crystal
structure at the proposed peptide-binding groove of DsbA. The
groove is formed between the active-site helix (a1) on the left
and the b5 strand-loop-a7 helix on the right. The
symmetry-related atoms Ser128^*-Phe129^*-Val130^* are shown in a
blue ball-and-stick representation, with Phe129^* labeled
(F129^*). The active-site Cys30 sulfur atom is shown as a yellow
CPK sphere. This figure was generated using MOLSCRIPT v2.0.1
[52] and Raster3D [53 and 54].
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The above figure is
reprinted
by permission from Cell Press:
Structure
(1998,
6,
757-767)
copyright 1998.
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Secondary reference #1
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Title
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Structural analysis of three his32 mutants of dsba: support for an electrostatic role of his32 in dsba stability.
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Authors
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L.W.Guddat,
J.C.Bardwell,
R.Glockshuber,
M.Huber-Wunderlich,
T.Zander,
J.L.Martin.
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Ref.
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Protein Sci, 1997,
6,
1893-1900.
[DOI no: ]
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PubMed id
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Secondary reference #2
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Title
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The uncharged surface features surrounding the active site of escherichia coli dsba are conserved and are implicated in peptide binding.
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Authors
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L.W.Guddat,
J.C.Bardwell,
T.Zander,
J.L.Martin.
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Ref.
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Protein Sci, 1997,
6,
1148-1156.
[DOI no: ]
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PubMed id
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Figure 1.
Fig. 1. Stereo view of the structure of oxidized wt E. coli DsbA (from monomer A in the asyrnmetnc unit). Thisfigure was prepared
with the program MOLSCRIPT (Kraulis, 1991).
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Figure 5.
Fig. 5. The proosed peptide interaction surface ofDsbA.Left:Amodelof
theinteractionbetweenpeptide substrate andDsbA,basedonthehuman
thioredoxin:Ref-1peptidecomplex[(Qin et al., 1996b) DB accession
code lCQG]. The electrostatic surface ofDsbAisshown[generatedusing
GRASP (Nicholls et al., 1993)] withthe peptide n the thioredoxin-bound
conformation superimposed. The positionof the accessible sulfur of the
active-site disulfide is denoted by S.'' Right: CPKmodelofDsbA,show-
ing uncharged inyellow. Residues ithat least one
occurrence ofacharged amino acid (Asp, Glu, Lys, or kg) inthenine
aligned sequences are showninwhite. The conserved active-site cysteines
are shownin green.
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The above figures are
reproduced from the cited reference
which is an Open Access publication published by the Protein Society
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Secondary reference #3
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Title
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Crystal structure of the dsba protein required for disulphide bond formation in vivo.
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Authors
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J.L.Martin,
J.C.Bardwell,
J.Kuriyan.
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Ref.
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Nature, 1993,
365,
464-468.
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PubMed id
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Secondary reference #4
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Title
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Crystallization of dsba, An escherichia coli protein required for disulphide bond formation in vivo.
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Authors
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J.L.Martin,
G.Waksman,
J.C.Bardwell,
J.Beckwith,
J.Kuriyan.
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Ref.
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J Mol Biol, 1993,
230,
1097-1100.
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PubMed id
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