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 September 2, 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 September 2, 2014).

Share This




More Matter & Energy News

Tuesday, September 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Google Teases India Event, Possible Android One Reveal

Google Teases India Event, Possible Android One Reveal

Newsy (Sep. 1, 2014) — Google has announced a Sept. 15 event in India during which they're expected to reveal their Android One phones. Video provided by Newsy
Powered by NewsLook.com
Australian Airlines Relax Phone Ban Too

Australian Airlines Relax Phone Ban Too

Reuters - Business Video Online (Aug. 26, 2014) — Qantas and Virgin say passengers can use their smartphones and tablets throughout flights after a regulator relaxed a ban on electronic devices during take-off and landing. As Hayley Platt reports the move comes as the two domestic rivals are expected to post annual net losses later this week. Video provided by Reuters
Powered by NewsLook.com
Hurricane Marie Brings Big Waves to California Coast

Hurricane Marie Brings Big Waves to California Coast

Reuters - US Online Video (Aug. 26, 2014) — Huge waves generated by Hurricane Marie hit the Southern California coast. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Chinese Researchers Might Be Creating Supersonic Submarine

Chinese Researchers Might Be Creating Supersonic Submarine

Newsy (Aug. 26, 2014) — Chinese researchers have expanded on Cold War-era tech and are closer to building a submarine that could reach the speed of sound. 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