Ion-Ion Repulsions and Charge-Shielding Effects Dominate the Permeation Mechanism through the OmpF Porin Channel

Juan Carlos Ahumada, Carlos Alemán, Jorge Soto-Delgado, Juan Torras

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

OmpF is a wide channel bacterial porin frequently employed to study selective ionic translocation. The cationic preference of this porin is mainly determined by electrostatic forces between the translocated ion and the protein and the formation of ion pairs (e.g., K+···Cl-) being previously pointed as the main cause to favor the cationic transport through the constriction zone. Hybrid quantum mechanics/molecular mechanics-molecular dynamics simulations, which have provided polarization-containing potentials of mean force profiles for different permeation scenarios, reveal significant new insights related with the ion translocation mechanism. Results show that the permeation is dominated by electrostatic interactions, which in turn affect ion-protein interactions at the constriction zone. However, it is observed that ion flow is favored by ion-ion repulsions and, in a lesser extent, by charge-shielding effects, instead of the previously pointed ionic pair formation.

Original languageEnglish
Pages (from-to)86-94
Number of pages9
JournalJournal of Physical Chemistry B
Volume123
Issue number1
DOIs
Publication statusAccepted/In press - 1 Jan 2018

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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