Elena García-Giménez

Universitat Jaume I

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Antonio Alcaraz

Universitat Jaume I

Vicente M. Aguilella

Universitat Jaume I

M. Lidón López

Iona College

María Queralt-Martín

Universitat Jaume I

Patricio Ramı́rez

Universitat Politècnica de València

Salvador Mafé

Universitat de València

Marcel Aguilella‐Arzo

Universitat Jaume I

Sergey M. Bezrukov

National Institutes of Health

Ekaterina M. Nestorovich

Catholic University of America

Andreu Andrio

Universitat Jaume I

Cooperative Institutions

Universitat Jaume I

Universitat de València

Universitat Politècnica de València

Fundación Hospital Provincial de Castellón

National Institutes of Health

Eunice Kennedy Shriver National Institute of Child Health and Human Development

Institute of Molecular Biology and Biophysics

Instituto de Ciencia y Tecnología de Polímeros

Eunice Kennedy Shriver Center

Nanyang Technological University

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Linearity, saturation and blocking in a large multiionic channel: Divalent cation modulation of the OmpF porin conductance

Biochemical and Biophysical Research Communications (2010)

Elena García-Giménez M. Lidón López Vicente M. Aguilella Antonio Alcaraz

Divalent

Saturation (graph theory)

Porin

10.1016/j.bbrc.2010.11.118

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Citations (16)

Divalent Cations Reduce the pH Sensitivity of OmpF Channel Inducing the PKA Shift of Key Acidic Residues

Biophysical Journal (2011)

María Queralt-Martín Elena García-Giménez Salvador Mafé Antonio Alcaraz

Divalent

10.1016/j.bpj.2010.12.2011

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Citations (0)

Electrical pumping of potassium ions against an external concentration gradient in a biological ion channel

Applied Physics Letters (2013)

María Queralt-Martín Elena García-Giménez Vicente M. Aguilella Patricio Ramı́rez Salvador Mafé

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 properties can be used to pump potassium ions against an external concentration gradient under asymmetric pH conditions. The results are discussed in terms of the ionic selectivity and rectification ratio of the channel. The physical concepts involved may be applied to separation processes with synthetic nanopores and to bioelectrical phenomena.

KcsA potassium channel

Porin

Concentration gradient

10.1063/1.4816748

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Citations (37)

Diffusion, Exclusion, and Specific Binding in a Large Channel: A Study of OmpF Selectivity Inversion

Biophysical Journal (2009)

Antonio Alcaraz Ekaterina M. Nestorovich M. Lidón López Elena García-Giménez Sergey M. Bezrukov

Divalent

Cationic polymerization

10.1016/j.bpj.2008.09.024

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Citations (81)

Overcharging Below the Nanoscale: Multivalent Cations Reverse the Ion Selectivity of a Biological Channel

Biophysical Journal (2010)

Antonio Alcaraz Elena García-Giménez M. Lidón López Andreu Andrio Vicente M. Aguilella

Charge density

Divalent

Surface charge

Cationic polymerization

10.1016/j.bpj.2009.12.104

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Negative Cooperativity in a Protein Ion Channel Revealed by Current Noise, Conductance and Selectivity Experiments

Biophysical Journal (2009)

Elena García-Giménez Vicente M. Aguilella Antonio Alcaraz

Cooperativity

Cooperative binding

Trimer

10.1016/j.bpj.2008.12.3185

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Directional Ion Selectivity In An Ion Channel With Bipolar Charge Distribution

Biophysical Journal (2009)

Elena García-Giménez Antonio Alcaraz M. Lidón López Vicente M. Aguilella Patricio Ramı́rez

Charge density

Reversal potential

Porin

10.1016/j.bpj.2008.12.3501

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Directional ion selectivity in a biological nanopore with bipolar structure

Journal of Membrane Science (2009)

Elena García-Giménez Antonio Alcaraz Vicente M. Aguilella Patricio Ramı́rez

Nanopore

Porin

10.1016/j.memsci.2009.01.026

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Citations (40)

Divalent cations reduce the pH sensitivity of OmpF channel inducing the pK_ashift of key acidic residues

Physical Chemistry Chemical Physics (2010)

María Queralt-Martín Elena García-Giménez Salvador Mafé Antonio Alcaraz

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 understanding the permeation mechanisms in ion channels and their regulation in vivo. The interaction between divalent cations and a protein channel, the bacterial porin OmpF, has been investigated paying attention to the channel selectivity and its dependence on the solution pH. Unlike the experiments performed in salts of monovalent cations, the channel is now practically insensitive to pH, being anion selective all over the pH range considered. Electrostatic calculations based on the available structural data suggest that the binding of divalent cations has two main effects: (i) the pKa values of key ionizable groups differ significantly from those of the isolated groups in solution and (ii) the cation binding has a decisive impact on the effective electric charge regulating the channel selectivity. A simple molecular model based on statistical thermodynamics provides additional qualitative explanations to the experimental findings that could also be useful for other related systems like synthetic nanopores, ion exchange membranes, and polyelectrolyte multilayers.

Divalent

Cationic polymerization

10.1039/c0cp01325k

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Citations (18)

Divalent Metal Ion Transport across Large Biological Ion Channels and Their Effect on Conductance and Selectivity

Biochemistry Research International (2012)

Elena García-Giménez Antonio Alcaraz Vicente M. Aguilella

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 decimolar concentrations buffered at neutral pH). We extend here the characterization of the OmpF porin, a wide channel of the outer membrane of E. coli, by studying the effect of salts of divalent cations on the transport properties of the channel. The regulation of divalent cations concentration is essential in cell metabolism and understanding their effects is of key importance, not only in the channels specifically designed to control their passage but also in other multiionic channels. In particular, in porin channels like OmpF, divalent cations modulate the efficiency of molecules having antimicrobial activity. Taking advantage of the fact that the OmpF channel atomic structure has been resolved both in water and in MgCl 2 aqueous solutions, we analyze the single channel conductance and the channel selectivity inversion aiming to separate the role of the electrolyte itself, and the counterion accumulation induced by the protein channel charges and other factors (binding, steric effects, etc.) that being of minor importance in salts of monovalent cations become crucial in the case of divalent cations.

Divalent

Porin

10.1155/2012/245786

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Citations (9)