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PDBsum entry 1z91
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DNA binding protein
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PDB id
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1z91
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References listed in PDB file
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Key reference
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Title
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Structure of an ohrr-Ohra operator complex reveals the DNA binding mechanism of the marr family.
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Authors
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M.Hong,
M.Fuangthong,
J.D.Helmann,
R.G.Brennan.
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Ref.
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Mol Cell, 2005,
20,
131-141.
[DOI no: ]
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PubMed id
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Abstract
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The mechanisms by which Bacillus subtilis OhrR, a member of the MarR family of
transcription regulators, binds the ohrA operator and is induced by oxidation of
its lone cysteine residue by organic hydroperoxides to sulphenic acid are
unknown. Here, we describe the crystal structures of reduced OhrR and an
OhrR-ohrA operator complex. To bind DNA, OhrR employs a chimeric winged
helix-turn-helix DNA binding motif, which is composed of extended
eukaryotic-like wings, prokaryotic helix-turn-helix motifs, and helix-helix
elements. The reactivity of the peroxide-sensing cysteine is not modulated by
proximal basic residues but largely by the positive dipole of helix alpha1.
Induction originates from the alleviation of intersubunit steric clash between
the sulphenic acid moieties of the oxidized sensor cysteines and nearby
tyrosines and methionines. The structure of the OhrR-ohrA operator complex
reveals the DNA binding mechanism of the entire MarR family and suggests a
common inducer binding pocket.
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Figure 2.
Figure 2. Structure of the OhrR-ohrA Operator Complex
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Figure 3.
Figure 3. OhrR-ohrA Operator Binding
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The above figures are
reprinted
by permission from Cell Press:
Mol Cell
(2005,
20,
131-141)
copyright 2005.
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