Ion Transport in Confined Geometries below the Nanoscale: Access Resistance Dominates Protein Channel Conductance in Diluted Solutions
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Otros documentos de la autoría: Alcaraz, Antonio; López Peris, María Lidón; Queralt-Martín, María; Aguilella, Vicente
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Mostrar el registro completo del ítemcomunitat-uji-handle:10234/9
comunitat-uji-handle2:10234/2507
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http://dx.doi.org/10.1021/acsnano.7b05529 |
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Título
Ion Transport in Confined Geometries below the Nanoscale: Access Resistance Dominates Protein Channel Conductance in Diluted SolutionsFecha de publicación
2017ISSN
1936-0851; 1936-086XCita bibliográfica
ALCARAZ, Antonio, et al. Ion Transport in Confined Geometries below the Nanoscale: Access Resistance Dominates Protein Channel Conductance in Diluted Solutions. ACS nano, 2017, vol. 11, no 10, p. 10392-10400.Tipo de documento
info:eu-repo/semantics/articleVersión de la editorial
https://pubs.acs.org/doi/full/10.1021/acsnano.7b05529Versión
info:eu-repo/semantics/publishedVersionPalabras clave / Materias
Resumen
Synthetic nanopores and mesoscopic protein channels have common traits like the importance of electrostatic interactions between the permeating ions and the nanochannel. Ion transport at the nanoscale occurs under ... [+]
Synthetic nanopores and mesoscopic protein channels have common traits like the importance of electrostatic interactions between the permeating ions and the nanochannel. Ion transport at the nanoscale occurs under confinement conditions so that the usual assumptions made in microfluidics are challenged, among others, by interfacial effects such as access resistance (AR). Here, we show that a sound interpretation of electrophysiological measurements in terms of channel ion selective properties requires the consideration of interfacial effects, up to the point that they dominate protein channel conductance in diluted solutions. We measure AR in a large ion channel, the bacterial porin OmpF, by means of single-channel conductance measurements in electrolyte solutions containing varying concentrations of high molecular weight PEG, sterically excluded from the pore. Comparison of experiments performed in charged and neutral planar membranes shows that lipid surface charges modify the ion distribution and determine the value of AR, indicating that lipid molecules are more than passive scaffolds even in the case of large transmembrane proteins. We also found that AR may reach up to 80% of the total channel conductance in diluted solutions, where electrophysiological recordings register essentially the AR of the system and depend marginally on the pore characteristics. These findings may have implications for several low aspect ratio biological channels that perform their physiological function in a low ionic strength and macromolecule crowded environment, just the two conditions enhancing the AR contribution. [-]
Publicado en
ACS nano, 2017, vol. 11, no 10Proyecto de investigación
Ministry of Economy and Competitiveness of Spain: FIS2013-40473-P; FIS2016-75257-P AEI/FEDER. Universitat Jaume I: P1.1B2015-28Derechos de acceso
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