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PDBsum entry 5frh
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Transcription
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PDB id
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5frh
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References listed in PDB file
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Key reference
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Title
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The anti-Sigma factor rsra responds to oxidative stress by reburying its hydrophobic core.
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Authors
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K.V.Rajasekar,
K.Zdanowski,
J.Yan,
J.T.Hopper,
M.L.Francis,
C.Seepersad,
C.Sharp,
L.Pecqueur,
J.M.Werner,
C.V.Robinson,
S.Mohammed,
J.R.Potts,
C.Kleanthous.
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Ref.
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Nat Commun, 2016,
7,
12194.
[DOI no: ]
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PubMed id
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Abstract
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Redox-regulated effector systems that counteract oxidative stress are essential
for all forms of life. Here we uncover a new paradigm for sensing oxidative
stress centred on the hydrophobic core of a sensor protein. RsrA is an
archetypal zinc-binding anti-sigma factor that responds to disulfide stress in
the cytoplasm of Actinobacteria. We show that RsrA utilizes its hydrophobic core
to bind the sigma factor σ(R) preventing its association with RNA polymerase,
and that zinc plays a central role in maintaining this high-affinity complex.
Oxidation of RsrA is limited by the rate of zinc release, which weakens the
RsrA-σ(R) complex by accelerating its dissociation. The subsequent trigger
disulfide, formed between specific combinations of RsrA's three zinc-binding
cysteines, precipitates structural collapse to a compact state where all
σ(R)-binding residues are sequestered back into its hydrophobic core, releasing
σ(R) to activate transcription of anti-oxidant genes.
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