Optogenetic tool elucidated: Researchers explain channelrhodopsin

Feb 28, 2012

Controlling nerve cells with the aid of light: this is made possible by optogenetics. It enables, for example, the investigation of neurobiological processes with unprecedented spatial and temporal precision. The key tool of optogenetics is the light-activated protein channelrhodopsin. Biophysicists from Bochum and Berlin have now succeeded in explaining the switching mechanism through an interdisciplinary approach. The researchers report on their findings in the Journal of Biological Chemistry.

Until now, little has been known about the mechanism of the protein - especially about how the channel opens. However, deeper understanding is a prerequisite in order to be able to use the light-controlled protein specifically for neurobiological applications. In a new, multi-disciplinary approach, the Bochum scientists led by Prof. Dr. Klaus Gerwert (Department of Biophysics at the RUB) and their cooperation partners in Berlin have been able to shed light on the switching mechanism. The result: the light-induced change in the charge state of amino acid glutamate 90 (E90) triggers an increased penetration of , so that the protein can now purposefully conduct ions through the .

Using time-resolved , the RUB biophysicists Jens Kuhne and Dr. Erik Freier have been able to show for the first time that the channel is opened through the deprotonation of the amino acid glutamate 90 (E90). In addition, the electrophysiological experiments of the researchers in Berlin confirm that a mutation of the amino acid leads to a change in the ion permeability of the protein. Instead of using safety goggles and lab coats, the two biophysicists Kirstin Eisenhauer and Dr. Steffen Wolf at the Department of used supercomputers to simulate how the protonation change of the glutamate opens the channel and allows water molecules to penetrate.

The work has attained particular distinction right now, because shortly after the Bochum pre-publication on the Internet, Japanese researchers published the three-dimensional structure of a channelrhodopsin online in "Nature". "The structure work impressively confirms our biomolecular simulations and the key role played by the amino acid E90 in the switching of the channel", says Prof. Klaus Gerwert. "We are therefore particularly proud to have been preeminent in this internationally competitive field." In 2010, optogenetics was distinguished by "Nature Methods" as the "Method of the Year". Using this method, researchers have succeeded, for example, in restoring the eyesight of blind mice.

Explore further: Oat breakfast cereals may contain a common mold-related toxin

More information: K. Eisenhauer, J. Kuhne, E. Ritter, A. Berndt, S. Wolf, E. Freier, F. Bartl, P. Hegemann, K. Gerwert,: In channelrhodopsin-2 E90 is crucial for ion selectivity and is deprotonated during the photocycle, Journal of Biological Chemistry, Vol. 287, Issue 9, 6904-6911, 2012, DOI: 10.1074/jbc.M111.327700

add to favorites email to friend print save as pdf

Related Stories

Researchers discover proton diode

Sep 02, 2010

Biophysicists in Bochum have discovered a diode for protons: just like the electronic component determines the direction of flow of electric current, the "proton diode" ensures that protons can only pass through ...

Controlling movements with light

Jul 20, 2011

German researchers at the Ruhr-Universitaet have succeeded in controlling the activity of certain nerve cells using light, thus influencing the movements of mice. By changing special receptors in nerve cells of the cerebellum ...

Recommended for you

Researchers bring clean energy a step closer

Feb 27, 2015

For nearly half a century, scientists have been trying to replace precious metal catalysts in fuel cells. Now, for the first time, researchers at Case Western Reserve University have shown that an inexpensive metal-free catalyst ...

The construction of ordered nanostructures from benzene

Feb 27, 2015

A way to link benzene rings together in a highly ordered three-dimensional helical structure using a straightforward polymerization procedure has been discovered by researchers from RIKEN Center for Sustainable ...

Superatomic nickel core and unusual molecular reactivity

Feb 27, 2015

A superatom is a combination of two or more atoms that form a stable structural fragment and possess unique physical and chemical properties. Systems, that contain superatoms, open a number of amazing possibilities ...

Oat breakfast cereals may contain a common mold-related toxin

Feb 25, 2015

Oats are often touted for boosting heart health, but scientists warn that the grain and its products might need closer monitoring for potential mold contamination. They report in ACS' Journal of Agricultural and Food Chemistry that s ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.