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 New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>