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 Molecular Force Sensors
20.09.2017 | Max-Planck-Institut für Biochemie

nachricht Foster tadpoles trigger parental instinct in poison frogs
20.09.2017 | Veterinärmedizinische Universität Wien

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Molecular Force Sensors

20.09.2017 | Life Sciences

Producing electricity during flight

20.09.2017 | Power and Electrical Engineering

Tiny lasers from a gallery of whispers

20.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>