Featured Research

from universities, journals, and other organizations

Water molecules control inactivation and recovery of potassium channels

Date:
July 28, 2013
Source:
University of Chicago Medical Center
Summary:
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, 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.

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

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.

"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 Benoξt 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."


Story Source:

The above story is based on materials provided by University of Chicago Medical Center. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jared Ostmeyer, Sudha Chakrapani, Albert C. Pan, Eduardo Perozo, Benoξt Roux. Recovery from slow inactivation in K channels is controlled by water molecules. Nature, 2013; DOI: 10.1038/nature12395

Cite This Page:

University of Chicago Medical Center. "Water molecules control inactivation and recovery of potassium channels." ScienceDaily. ScienceDaily, 28 July 2013. <www.sciencedaily.com/releases/2013/07/130728134055.htm>.
University of Chicago Medical Center. (2013, July 28). Water molecules control inactivation and recovery of potassium channels. ScienceDaily. Retrieved April 19, 2014 from www.sciencedaily.com/releases/2013/07/130728134055.htm
University of Chicago Medical Center. "Water molecules control inactivation and recovery of potassium channels." ScienceDaily. www.sciencedaily.com/releases/2013/07/130728134055.htm (accessed April 19, 2014).

Share This



More Matter & Energy News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Small Reactors Could Be Future of Nuclear Energy

Small Reactors Could Be Future of Nuclear Energy

AP (Apr. 17, 2014) — After the Fukushima nuclear disaster, the industry fell under intense scrutiny. Now, small underground nuclear power plants are being considered as the possible future of the nuclear energy. (April 17) Video provided by AP
Powered by NewsLook.com
Horseless Carriage Introduced at NY Auto Show

Horseless Carriage Introduced at NY Auto Show

AP (Apr. 17, 2014) — An electric car that proponents hope will replace horse-drawn carriages in New York City has also been revealed at the auto show. (Apr. 17) Video provided by AP
Powered by NewsLook.com
Honda's New ASIMO Robot, More Human-Like Than Ever

Honda's New ASIMO Robot, More Human-Like Than Ever

AFP (Apr. 17, 2014) — It walks and runs, even up and down stairs. It can open a bottle and serve a drink, and politely tries to shake hands with a stranger. Meet the latest ASIMO, Honda's humanoid robot. Duration: 00:54 Video provided by AFP
Powered by NewsLook.com
German Researchers Crack Samsung's Fingerprint Scanner

German Researchers Crack Samsung's Fingerprint Scanner

Newsy (Apr. 16, 2014) — German researchers have used a fake fingerprint made from glue to bypass the fingerprint security system on Samsung's new Galaxy S5 smartphone. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins