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PDBsum entry 3wu6
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References listed in PDB file
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Key reference
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Title
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A redox switch shapes the lon protease exit pore to facultatively regulate proteolysis.
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Authors
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W.Nishii,
M.Kukimoto-Niino,
T.Terada,
M.Shirouzu,
T.Muramatsu,
M.Kojima,
H.Kihara,
S.Yokoyama.
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Ref.
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Nat Chem Biol, 2015,
11,
46-51.
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PubMed id
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Abstract
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The Lon AAA+ protease degrades damaged or misfolded proteins in its
intramolecular chamber. Its activity must be precisely controlled, but the
mechanism by which Lon is regulated in response to different environments is not
known. Facultative anaerobes in the Enterobacteriaceae family, mostly symbionts
and pathogens, encounter both anaerobic and aerobic environments inside and
outside the host's body, respectively. The bacteria characteristically have two
cysteine residues on the Lon protease (P) domain surface that unusually form a
disulfide bond. Here we show that the cysteine residues act as a redox switch of
Lon. Upon disulfide bond reduction, the exit pore of the P-domain ring narrows
by ∼30%, thus interrupting product passage and decreasing activity by 80%;
disulfide bonding by oxidation restores the pore size and activity. The redox
switch (E°' = -227 mV) is appropriately tuned to respond to variation between
anaerobic and aerobic conditions, thus optimizing the cellular proteolysis level
for each environment.
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