Listar por autoría "38f80378-3ffd-40a4-bf14-b00032a0efb6"
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Diffusion, exclusion, and specific binding in a large channel: A study of OmpF selectivity inversion
Alcaraz, Antonio; Nestorovich E.M.; López Peris, María Lidón; García Giménez, Elena; Bezrukov S.M.; Aguilella, Vicente Elsevier (2009)We find that moderate cationic selectivity of the general bacterial porin OmpF in sodium and potassium chloride solutions is inversed to anionic selectivity in concentrated solutions of barium, calcium, nickel, and magnesium ... -
Directional ion selectivity in a biological nanopore with bipolar structure
García Giménez, Elena; Alcaraz, Antonio; Aguilella, Vicente; Ramírez, Patricio Elsevier (2009)Ion transport features of a biological nanopore, the bacterial porin OmpF from Escherichia coli, have been investigated by patch-clamp experiments performed at the single channel level. Membrane potential measurements done ... -
Divalent cations reduce the pH sensitivity of OmpF channel inducing the pKa shift of key acidic residues
Queralt-Martín, María; Alcaraz, Antonio; García Giménez, Elena; Mafe, Salvador RSC Publishing (2010-11-03)In contrast to the highly-selective channels of neurophysiology employing mostly the exclusion mechanism, different factors account for the selectivity of large channels. Elucidation of these factors is essential for ... -
Divalent Metal Ion Transport across Large Biological Ion Channels and Their Effect on Conductance and Selectivity
García Giménez, Elena; Alcaraz, Antonio; Aguilella, Vicente Hindawi Publishing Corporation (2012-07)Electrophysiological characterization of large protein channels, usually displaying multi-ionic transport and weak ion selectivity, is commonly performed at physiological conditions (moderate gradients of KCl solutions at ... -
Electrical pumping of potassium ions against an external concentration gradient in a biological ion channel
Aguilella, Vicente; Alcaraz, Antonio; Ramírez, Patricio; García Giménez, Elena; Mafe, Salvador; Queralt-Martín, María AIP Publishing (2013-07-22)We show experimentally and theoretically that significant currents can be obtained with a biological ion channel, the OmpF porin of Escherichia coli, using zero-average potentials as driving forces. The channel rectifying ... -
Increased salt concentration promotes competitive block of OmpF channel by protons
Alcaraz, Antonio; García Giménez, Elena; Aguilella, Vicente; Queralt-Martín, María Elsevier (2012-11)Porins are channel-forming proteins that are located in the outer membranes (OM) of Gram-negative bacteria and allow the influx of hydrophilic nutrients and the extrusion of waste products. The fine regulation of the ion ... -
Linearity, saturation and blocking in a large multiionic channel: divalent cation modulation of the OmpF porin conductance
García Giménez, Elena; López Peris, María Lidón; Aguilella, Vicente; Alcaraz, Antonio Elsevier (2011-01)Measurement of unitary conductance is a fundamental step in the characterization of a protein ion channelpermeabilizing a membrane. We study here the effect of salts of divalent cations on the OmpF channelconductance ... -
Selectivity of Protein Ion Channels and the Role of Buried Charges. Analytical Solutions, Numerical Calculations, and MD Simulations
García Giménez, Elena; Alcaraz, Antonio; Aguilella-Arzo, Marcel; Aguilella, Vicente American Chemical Society (2015-06)The preference of large protein ion channels for cations or anions is mainly determined by the electrostatic interactions of mobile ions with charged residues of the protein. Here we discuss the widely spread paradigm that ...