4 research outputs found
A Structural Study of Ion Permeation in OmpF Porin from Anomalous X‑ray Diffraction and Molecular Dynamics Simulations
OmpF, a multiionic porin from <i>Escherichia coli</i>, is a useful protypical model system for
addressing general questions
about electrostatic interactions in the confinement of an aqueous
molecular pore. Here, favorable anion locations in the OmpF pore were
mapped by anomalous X-ray scattering of Br<sup>–</sup> ions
from four different crystal structures and compared with Mg<sup>2+</sup> sites and Rb<sup>+</sup> sites from a previous anomalous diffraction
study to provide a complete picture of cation and anion transfer paths
along the OmpF channel. By comparing structures with various crystallization
conditions, we find that anions bind in discrete clusters along the
entire length of the OmpF pore, whereas cations find conserved binding
sites with the extracellular, surface-exposed loops. Results from
molecular dynamics simulations are consistent with the experimental
data and help highlight the critical residues that preferentially
contact either cations or anions during permeation. Analysis of these
results provides new insights into the molecular mechanisms that determine
ion selectivity in OmpF porin
A Structural Study of Ion Permeation in OmpF Porin from Anomalous X‑ray Diffraction and Molecular Dynamics Simulations
OmpF, a multiionic porin from <i>Escherichia coli</i>, is a useful protypical model system for
addressing general questions
about electrostatic interactions in the confinement of an aqueous
molecular pore. Here, favorable anion locations in the OmpF pore were
mapped by anomalous X-ray scattering of Br<sup>–</sup> ions
from four different crystal structures and compared with Mg<sup>2+</sup> sites and Rb<sup>+</sup> sites from a previous anomalous diffraction
study to provide a complete picture of cation and anion transfer paths
along the OmpF channel. By comparing structures with various crystallization
conditions, we find that anions bind in discrete clusters along the
entire length of the OmpF pore, whereas cations find conserved binding
sites with the extracellular, surface-exposed loops. Results from
molecular dynamics simulations are consistent with the experimental
data and help highlight the critical residues that preferentially
contact either cations or anions during permeation. Analysis of these
results provides new insights into the molecular mechanisms that determine
ion selectivity in OmpF porin
A Structural Study of Ion Permeation in OmpF Porin from Anomalous X‑ray Diffraction and Molecular Dynamics Simulations
OmpF, a multiionic porin from <i>Escherichia coli</i>, is a useful protypical model system for
addressing general questions
about electrostatic interactions in the confinement of an aqueous
molecular pore. Here, favorable anion locations in the OmpF pore were
mapped by anomalous X-ray scattering of Br<sup>–</sup> ions
from four different crystal structures and compared with Mg<sup>2+</sup> sites and Rb<sup>+</sup> sites from a previous anomalous diffraction
study to provide a complete picture of cation and anion transfer paths
along the OmpF channel. By comparing structures with various crystallization
conditions, we find that anions bind in discrete clusters along the
entire length of the OmpF pore, whereas cations find conserved binding
sites with the extracellular, surface-exposed loops. Results from
molecular dynamics simulations are consistent with the experimental
data and help highlight the critical residues that preferentially
contact either cations or anions during permeation. Analysis of these
results provides new insights into the molecular mechanisms that determine
ion selectivity in OmpF porin
A Structural Study of Ion Permeation in OmpF Porin from Anomalous X‑ray Diffraction and Molecular Dynamics Simulations
OmpF, a multiionic porin from <i>Escherichia coli</i>, is a useful protypical model system for
addressing general questions
about electrostatic interactions in the confinement of an aqueous
molecular pore. Here, favorable anion locations in the OmpF pore were
mapped by anomalous X-ray scattering of Br<sup>–</sup> ions
from four different crystal structures and compared with Mg<sup>2+</sup> sites and Rb<sup>+</sup> sites from a previous anomalous diffraction
study to provide a complete picture of cation and anion transfer paths
along the OmpF channel. By comparing structures with various crystallization
conditions, we find that anions bind in discrete clusters along the
entire length of the OmpF pore, whereas cations find conserved binding
sites with the extracellular, surface-exposed loops. Results from
molecular dynamics simulations are consistent with the experimental
data and help highlight the critical residues that preferentially
contact either cations or anions during permeation. Analysis of these
results provides new insights into the molecular mechanisms that determine
ion selectivity in OmpF porin