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Title
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Properties of deactivation gating currents in shaker channels
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Author
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Abstract
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| The charge versus voltage relation of voltage-sensor domains shifts in the voltage axis depending on the initial voltage. Here we show that in nonconducting W434F Shaker K+ channels, a large portion of this charge-voltage shift is apparent due to a dramatic slowing of the deactivation gating currents, IgD (with τ up to 80 ms), which develops with a time course of not, vert, similar1.8 s. This slowing in IgD adds up to the slowing due to pore opening and is absent in the presence of 4-aminopyridine, a compound that prevents the last gating step that leads to pore opening. A remaining 1015 mV negative shift in the voltage dependence of both the kinetics and the charge movement persists independently of the depolarizing prepulse duration and remains in the presence of 4-aminopyridine, suggesting the existence of an intrinsic offset in the local electric field seen by activated channels. We propose a new (to our knowledge) kinetic model that accounts for these observations. |
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Language
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English
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Source (journal)
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Biophysical journal. - New York, N.Y.
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Publication
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New York, N.Y.
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2011
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ISSN
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0006-3495
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DOI
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10.1016/J.BPJ.2011.01.043
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Volume/pages
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100
:5
(2011)
, p. L28-L30
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ISI
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000288049400002
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Full text (Publisher's DOI)
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Full text (open access)
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