4LSE

Ion selectivity of OmpF porin soaked in 0.2M NaBr

Summary for 4LSE

• Entry DOI: 10.2210/pdb4lse/pdb
• Related: 4LSF 4LSH 4LSI
• Descriptor: Outer membrane protein F, BROMIDE ION, MAGNESIUM ION, ... (6 entities in total)
• Functional Keywords: porin, outer membrane protein, beta-barrel, ion transport, transport protein
• Biological source: Escherichia coli
• Cellular location: Cell outer membrane; Multi-pass membrane protein: P02931
• Total number of polymer chains: 3
• Total formula weight: 113336.32

Authors

Balasundaresan, D.,Blachowicz, L.,Roux, B. (deposition date: 2013-07-22, release date: 2013-10-23, Last modification date: 2023-09-20)

Primary citation

Dhakshnamoorthy, B.,Ziervogel, B.K.,Blachowicz, L.,Roux, B.
A structural study of ion permeation in OmpF porin from anomalous X-ray diffraction and molecular dynamics simulations.
J.Am.Chem.Soc., 135:16561-16568, 2013

PubMed Abstract: OmpF, a multiionic porin from Escherichia coli, 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(–) ions from four different crystal structures and compared with Mg(2+) sites and Rb(+) 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.

PubMed: 24106986
DOI: 10.1021/ja407783a

Experimental method

X-RAY DIFFRACTION (2.1 Å)