Principles of Selective Ion Transport in Channels and Pumps

  title={Principles of Selective Ion Transport in Channels and Pumps},
  author={Eric Gouaux and Roderick MacKinnon},
  pages={1461 - 1465}
The transport of ions across the membranes of cells and organelles is a prerequisite for many of life's processes. Transport often involves very precise selectivity for specific ions. Recently, atomic-resolution structures have been determined for channels or pumps that are selective for sodium, potassium, calcium, and chloride: four of the most abundant ions in biology. From these structures we can begin to understand the principles of selective ion transport in terms of the architecture and… 

Determinants of cation transport selectivity: Equilibrium binding and transport kinetics

The relationship between cation transport protein structures, equilibrium binding measurements, and ion transport selectivity is explored, focusing on K+-selective channels and nonselective cation channels.

Ion transport through cell membrane channels

Various models of ion transport through cell membrane channels are discussed, including microscopic Brownian and molecular dynamics and macroscopic continuum models based on Poisson-Nernst-Planck equations.

A structural overview of the plasma membrane Na+,K+-ATPase and H+-ATPase ion pumps

Structural information provides insight into the function of these two distinct but related P-type pumps, which maintain a proton gradient in plants and fungi and a Na+ and K+ gradient in animal cells.

Cell Membrane Transport Mechanisms: Ion Channels and Electrical Properties of Cell Membranes.

The present chapter addresses the questions how the cell membrane accomplishes transport functions and how transmembrane transport can be affected and reports how specific transport mechanisms can be modulated or inhibited in order to enhance the therapeutic effect.

Synthetic ion channels in bilayer membranes.

  • T. Fyles
  • Biology, Chemistry
    Chemical Society reviews
  • 2007
This tutorial review examines the design, synthesis, incorporation, and characterization of synthetic ion channels in bilayer membranes, and points to potential applications of synthetic Ion channels.

Primers on Molecular Pathways – Ion Channels: Key Regulators of Pancreatic Physiology

The interest in these molecules has increased due to the recognition of diverse pathologies related with mutations in genes encoding these transmembrane proteins, now known as channelopathies.

Mathematical models of ion transport through cell membrane channels

A derivation of the Poisson-Nernst-Planck equations is presented and some recent models of ion transport through cell membrane chan- nels are reviewed such as single-file diusion and Markov chains of interacting ions.



Gating the Selectivity Filter in ClC Chloride Channels

A form of gating is revealed in which the glutamate carboxyl group closes the pore by mimicking a Cl– ion, which governs the electrical activity of muscle cells and certain neurons.

Structure of a glycerol-conducting channel and the basis for its selectivity.

The crystal structure of the Escherichia coli glycerol facilitator (GlpF) elucidates the mechanism of selective permeability for linear carbohydrates and suggests how ions and water are excluded.

Secondary active transport mediated by a prokaryotic homologue of ClC Cl- channels

It is shown that this bacterial homologue of ClC-ec1 is not an ion channel, but rather a H+-Cl- exchange transporter, suggesting that the structural boundary separating channels and transporters is not as clear cut as generally thought.

Structural changes in the calcium pump accompanying the dissociation of calcium

The structure of the enzyme stabilized by thapsigargin, a potent inhibitor, shows large conformation differences from that in E1Ca2+.

Crystal structure of a bacterial homologue of Na+/Cl--dependent neurotransmitter transporters

The structure of a bacterial homologue of these transporters from Aquifex aeolicus, in complex with its substrate, leucine, and two sodium ions, is presented and reveals the architecture of this important class of transporter, illuminates the determinants of substrate binding and ion selectivity, and defines the external and internal gates.

Crystal structure of the calcium pump of sarcoplasmic reticulum at 2.6 Å resolution

Comparison with a low-resolution electron density map of the enzyme in the absence of calcium and with biochemical data suggests that large domain movements take place during active transport.

Structural basis of ion pumping by Ca2+-ATPase

Comparison of the structures of the Ca2+-ATPase (SERCA1a) for five different states by X-ray crystallography reveals that very large rearrangements of the transmembrane helices take place accompanyingCa2+ dissociation and binding and that they are mechanically linked with equally large movements of the cytoplasmic domains.

The structure of the potassium channel: molecular basis of K+ conduction and selectivity.

The architecture of the pore establishes the physical principles underlying selective K+ conduction, which promotes ion conduction by exploiting electrostatic repulsive forces to overcome attractive forces between K+ ions and the selectivity filter.