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PDBsum entry 2vyc
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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 structure of the acid-Induced arginine decarboxylase from escherichia coli: reversible decamer assembly controls enzyme activity.
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Authors
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J.Andréll,
M.G.Hicks,
T.Palmer,
E.P.Carpenter,
S.Iwata,
M.J.Maher.
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Ref.
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Biochemistry, 2009,
48,
3915-3927.
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PubMed id
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Abstract
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The acid-induced arginine decarboxylase is part of an enzymatic system in
Escherichia coli that contributes to making this organism acid resistant. The
arginine decarboxylase is a vitamin B(6)-dependent enzyme that is active at
acidic pH. It consumes a proton in the decarboxylation of arginine to agmatine,
and by working in tandem with an arginine-agmatine antiporter, this enzymatic
cycle protects the organism by preventing the accumulation of protons inside the
cell. We have determined the structure of the acid-induced arginine
decarboxylase by X-ray crystallography to 2.4 A resolution. The arginine
decarboxylase structure revealed a ca. 800 kDa decamer composed as a pentamer of
five homodimers. Each homodimer has an abundance of acidic surface residues,
which at neutral pH prevents inactive homodimers from associating into active
decamers. Conversely, acidic conditions favor the assembly of active decamers.
Therefore, the structure of arginine decarboxylase presents a mechanism by which
its activity is modulated by external pH.
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