Ionic transport through a protein nanopore: a Coarse-Grained Molecular Dynamics Study

Fuente: arXiv
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Main Authors: Nathalie, Basdevant, Delphine, Dessaux, Rosa, Ramirez
Format: Preprint
Published: 2018
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author Nathalie, Basdevant
Delphine, Dessaux
Rosa, Ramirez
author_facet Nathalie, Basdevant
Delphine, Dessaux
Rosa, Ramirez
contents The MARTINI coarse-grained (CG) force field is used to test the ability of CG models to simulate ionic transport through protein nanopores. The ionic conductivity of CG ions in solution was computed and compared with experimental results. Next, we studied the electrostatic behavior of a solvated CG lipid bilayer in salt solution under an external electric field. We showed this approach correctly describes the experimental conditions under a potential bias. Finally, we performed CG molecular dynamics simulations of the ionic transport through a protein nanopore ($α$-hemolysin) inserted in a lipid bilayer, under different electric fields, for 2-3 microseconds. The resulting $I-V$ curve is qualitatively consistent with experiments, although the computed current is one order of magnitude smaller. Current saturation was observed for potential biases over $\pm~350$~mV. We also discuss the time to reach a stationary regime and the role of the protein flexibility in our CG simulations.
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id arxiv_https___arxiv_org_abs_1810_09918
institution arXiv
publishDate 2018
record_format arxiv
spellingShingle Ionic transport through a protein nanopore: a Coarse-Grained Molecular Dynamics Study
Nathalie, Basdevant
Delphine, Dessaux
Rosa, Ramirez
Biological Physics
The MARTINI coarse-grained (CG) force field is used to test the ability of CG models to simulate ionic transport through protein nanopores. The ionic conductivity of CG ions in solution was computed and compared with experimental results. Next, we studied the electrostatic behavior of a solvated CG lipid bilayer in salt solution under an external electric field. We showed this approach correctly describes the experimental conditions under a potential bias. Finally, we performed CG molecular dynamics simulations of the ionic transport through a protein nanopore ($α$-hemolysin) inserted in a lipid bilayer, under different electric fields, for 2-3 microseconds. The resulting $I-V$ curve is qualitatively consistent with experiments, although the computed current is one order of magnitude smaller. Current saturation was observed for potential biases over $\pm~350$~mV. We also discuss the time to reach a stationary regime and the role of the protein flexibility in our CG simulations.
title Ionic transport through a protein nanopore: a Coarse-Grained Molecular Dynamics Study
topic Biological Physics
url https://arxiv.org/abs/1810.09918