Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New channel built

13.03.2002


Hinge benefits: ions pour through this synthetic chloride channel


Chemists copy from cells to make a tunnel for salt

Chemists have finally achieved what every human cell can do. They have designed and built from scratch a gate for electrically charged chlorine atoms to pass through1.

George Gokel and colleagues at Washington University in St Louis, Missouri, based their gate on biological proteins that transport chloride ions from one side of our cell membranes to the other. Like these, the synthetic channel can be opened and closed by applying a voltage. How this happens is not clear, even in natural ion channels.



In nature, voltage regulates ion flow to control how salty cells become. If there are more chloride ions on one side of a membrane than the other, the imbalance of electrical charge sets up a voltage across the membrane that can start or stop ions passing.

Cells use ion channels to produce electrical signals such as nerve impulses and the muscle movements that produce the heart beat. Many channels transport only one kind of ion, sodium, say, or chloride.

Similarly, the artificial channels transport chloride ions much more effectively than other ions, such as potassium or sulphate. Gokel’s group tested them in artificial particles called liposomes, which are hollow shells with walls like real cell membranes.

Several different types of protein-based chloride channel in the human body serve functions ranging from salt uptake to muscle contraction. Genetic mutations that make channels faulty are linked to heritable diseases such as cystic fibrosis and some muscle and kidney complaints.

Artificial chloride channels might one day serve as drugs against such diseases, but that’s a distant goal. At the moment, Gokel and his colleagues are simply trying to build simple molecules that can do the same job as real ion channels. Another motivation is that natural and synthetic ion transporters can act as antibiotics.

Channel tunnel

Cell membranes have an oily inside edge that repels water, so water-soluble substances such as ions need help getting across. Protein ion channels are embedded in a membrane, creating a kind of tunnel that lets ions through.

The new synthetic chloride channel tries to copy this. The molecule has a fatty, oil-soluble tail and a protein-like, ion-transporting head. The fatty tail anchors it in the membrane. The head contains a string of seven amino acids, like those that make up natural chloride channels. In particular, an amino acid known as proline is in the middle of the sequence.

Gokel’s team think that the proline is the hinge-like apex of an arch-shaped structure, and that two prolines stick together in the membrane to form a pore just wide enough for a chloride ion to pass through.

References

  • Schlesinger, P. H. et al. SCMTR: a chloride-selective, membrane-anchored peptide channel that exhibits voltage gating. Journal of the American Chemical Society, 124, 1848 - 1849, (2002).


PHILIP BALL | © Nature News Service

More articles from Life Sciences:

nachricht Microbes can grow on nitric oxide (NO)
18.03.2019 | Max-Planck-Institut für Marine Mikrobiologie

nachricht Novel methods for analyzing neural circuits for innate behaviors in insects
15.03.2019 | Kanazawa University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Revealing the secret of the vacuum for the first time

New research group at the University of Jena combines theory and experiment to demonstrate for the first time certain physical processes in a quantum vacuum

For most people, a vacuum is an empty space. Quantum physics, on the other hand, assumes that even in this lowest-energy state, particles and antiparticles...

Im Focus: Sussex scientists one step closer to a clock that could replace GPS and Galileo

Physicists in the EPic Lab at University of Sussex make crucial development in global race to develop a portable atomic clock

Scientists in the Emergent Photonics Lab (EPic Lab) at the University of Sussex have made a breakthrough to a crucial element of an atomic clock - devices...

Im Focus: Sensing shakes

A new way to sense earthquakes could help improve early warning systems

Every year earthquakes worldwide claim hundreds or even thousands of lives. Forewarning allows people to head for safety and a matter of seconds could spell...

Im Focus: A thermo-sensor for magnetic bits

New concept for energy-efficient data processing technology

Scientists of the Department of Physics at the University of Hamburg, Germany, detected the magnetic states of atoms on a surface using only heat. The...

Im Focus: The moiré patterns of three layers change the electronic properties of graphene

Combining an atomically thin graphene and a boron nitride layer at a slightly rotated angle changes their electrical properties. Physicists at the University of Basel have now shown for the first time the combination with a third layer can result in new material properties also in a three-layer sandwich of carbon and boron nitride. This significantly increases the number of potential synthetic materials, report the researchers in the scientific journal Nano Letters.

Last year, researchers in the US caused a big stir when they showed that rotating two stacked graphene layers by a “magical” angle of 1.1 degrees turns...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Researchers measure near-perfect performance in low-cost semiconductors

18.03.2019 | Power and Electrical Engineering

Nanocrystal 'factory' could revolutionize quantum dot manufacturing

18.03.2019 | Materials Sciences

Long-distance quantum information exchange -- success at the nanoscale

18.03.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>