Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Water molecules control inactivation and recovery of potassium channels

29.07.2013
Just 12 molecules of water cause the long post-activation recovery period required by potassium ion channels before they can function again.

Using molecular simulations that modeled a potassium channel and its immediate cellular environment, atom for atom, University of Chicago scientists have revealed this new mechanism in the function of a nearly universal biological structure, with implications ranging from fundamental biology to the design of pharmaceuticals. Their findings were published online July 28 in Nature.


Depiction of simulated potassium channel and surrounding environment. Potassium ions (green) are unable to pass through because water molecules (red and white) are present inside the protein, locking the channel into an inactivated state.

Credit: Benoit Roux, University of Chicago

"Our research clarifies the nature of this previously mysterious inactivation state. This gives us better understanding of fundamental biology and should improve the rational design of drugs, which often target the inactivated state of channels" said Benoît Roux, PhD, professor of biochemistry and molecular biology at the University of Chicago.

Potassium channels, present in the cells of virtually living organisms, are core components in bioelectricity generation and cellular communication. Required for functions such as neural firing and muscle contraction, they serve as common targets in pharmaceutical development.

These proteins act as a gated tunnel through the cell membrane, controlling the flow of small ions into and out of cells. After being activated by an external signal, potassium channels open to allow ions through. Soon after, however, they close, entering an inactive state and are unable to respond to stimuli for 10 to up to 20 seconds.

The cause of this long recovery period, which is enormously slow by molecular standards, has remained a mystery, as structural changes in the protein are known to be almost negligible between the active and inactivated states—differing by a distance equivalent to the diameter of a single carbon atom.

To shed light on this phenomenon, Roux and his team used supercomputers to simulate the movement and behavior of every individual atom in the potassium channel and its immediate environment. After computations corresponding to millions of core-hours, the team discovered that just 12 water molecules were responsible for the slow recovery of these channels.

They found that when the potassium channel is open, water molecules quickly bind to tiny cavities within the protein structure, where they block the channel in a state that prevents the passage of ions. The water molecules are released slowly only after the external stimulus has been removed, allowing the channel to be ready for activation again. This computer simulation-based finding was then confirmed through osmolarity experiments in the laboratory.

"Observing this was a complete surprise, but it made a lot of sense in retrospect," Roux said. "Better understanding of this ubiquitous biological system will change how people think about inactivation and recovery of these channels, and has the potential to someday impact human health."

The work was supported by grants from the National Institutes of Health. Computation resources were provided by Oak Ridge National Laboratory, the National Resource for Biomedical Supercomputing and the Pittsburgh Supercomputing Center.

Kevin Jiang | EurekAlert!
Further information:
http://www.uchospitals.edu

More articles from Life Sciences:

nachricht Antimicrobial substances identified in Komodo dragon blood
23.02.2017 | American Chemical Society

nachricht New Mechanisms of Gene Inactivation may prevent Aging and Cancer
23.02.2017 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)

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

From rocks in Colorado, evidence of a 'chaotic solar system'

23.02.2017 | Physics and Astronomy

'Quartz' crystals at the Earth's core power its magnetic field

23.02.2017 | Earth Sciences

Antimicrobial substances identified in Komodo dragon blood

23.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>