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PDBsum entry 5e1j
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Metal transport
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PDB id
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5e1j
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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 the voltage-Gated two-Pore channel tpc1 from arabidopsis thaliana.
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Authors
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J.Guo,
W.Zeng,
Q.Chen,
C.Lee,
L.Chen,
Y.Yang,
C.Cang,
D.Ren,
Y.Jiang.
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Ref.
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Nature, 2016,
531,
196-201.
[DOI no: ]
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PubMed id
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Abstract
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Two-pore channels (TPCs) contain two copies of a Shaker-like six-transmembrane
(6-TM) domain in each subunit and are ubiquitously expressed in both animals and
plants as organellar cation channels. Here we present the crystal structure of a
vacuolar two-pore channel from Arabidopsis thaliana, AtTPC1, which functions as
a homodimer. AtTPC1 activation requires both voltage and cytosolic Ca(2+).
Ca(2+) binding to the cytosolic EF-hand domain triggers conformational changes
coupled to the pair of pore-lining inner helices from the first 6-TM domains,
whereas membrane potential only activates the second voltage-sensing domain, the
conformational changes of which are coupled to the pair of inner helices from
the second 6-TM domains. Luminal Ca(2+) or Ba(2+) can modulate voltage
activation by stabilizing the second voltage-sensing domain in the resting state
and shift voltage activation towards more positive potentials. Our Ba(2+)-bound
AtTPC1 structure reveals a voltage sensor in the resting state, providing
hitherto unseen structural insight into the general voltage-gating mechanism
among voltage-gated channels.
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