Excess white noise to probe transport mechanisms in a membrane channel
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Other documents of the author: Queralt-Martín, María; López Peris, María Lidón; Alcaraz, Antonio
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Show full item recordcomunitat-uji-handle:10234/9
comunitat-uji-handle2:10234/2507
comunitat-uji-handle3:10234/6973
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Title
Excess white noise to probe transport mechanisms in a membrane channelDate
2015Publisher
American Physical SocietyISSN
1539-3755; 1550-2376Type
info:eu-repo/semantics/articlePublisher version
http://journals.aps.org/pre/abstract/10.1103/PhysRevE.91.062704Version
info:eu-repo/semantics/publishedVersionSubject
Abstract
Current fluctuation analysis has been successfully used over the years to investigate the physical properties
of different systems. Here, we perform single-channel time-resolved current experiments in a protein channel ... [+]
Current fluctuation analysis has been successfully used over the years to investigate the physical properties
of different systems. Here, we perform single-channel time-resolved current experiments in a protein channel to
evaluate the different transport mechanisms governing the channel function. Using different salts of monovalent
and divalent cations in a wide range of concentrations and applied potentials, we analyze current fluctuations
focusing on the voltage dependence of the additional white noise that appears in the low-frequency range of the
spectra. We demonstrate that the channel displays two characteristic transport regimes: at low salt concentrations
(10 mM to 1 M) ion permeation is controlled by the protein fixed charges that induce accumulation or exclusion
of ions to preserve local electroneutrality. At high salt concentrations (>1 M) adsorption processes associated to
the binding of cations to the channel charges regulate the transport properties. [-]
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PHYSICAL REVIEW E 91, 062704 (2015)Rights
©2015 American Physical Society
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