Featured Research

from universities, journals, and other organizations

Protein 'filmed' while unfolding at atomic resolution

Date:
February 11, 2013
Source:
Max Planck Institute for Biophysical Chemistry
Summary:
Whether Alzheimer’s, Parkinson’s or Huntington’s Chorea – all three diseases have one thing in common: They are caused by misfolded proteins that form insoluble clumps in the brains of affected patients and, finally, destroy their nerve cells. One of the most important questions in the biological sciences and medicine is thus: How do proteins – the tools of living cells – achieve or lose their three-dimensional structure. Because only if their amino acid chains are correctly folded, can proteins perform their tasks properly.

“Snapshot” of the unfolding of the CylR2 protein from Enterococcus faecalis. If the protein is cooled from 25°C to -16°C, it successively breaks down into its two identical subunits. The latter are initially stable, but at -16°C they form an instable, dynamic protein form, which plays a key role in folding.
Credit: Image courtesy of Max Planck Institute for Biophysical Chemistry

Whether Alzheimer's, Parkinson's or Huntington's Chorea -- all three diseases have one thing in common: They are caused by misfolded proteins that form insoluble clumps in the brains of affected patients and, finally, destroy their nerve cells. One of the most important questions in the biological sciences and medicine is thus: How do proteins -- the tools of living cells -- achieve or lose their three-dimensional structure. Because only if their amino acid chains are correctly folded, can proteins perform their tasks properly.

But what exactly happens when proteins fold or unfold was previously nearly impossible to investigate. With heat and pressure, proteins easily lose their shape -- and thus their function. However, such methods are not suitable for directly observing their unfolding process. The intermediate forms that occur in the course of protein folding are much too transient.

With a novel approach, researchers have now succeeded in "filming" the complex process of protein folding for the first time. Scientists at the Max Planck Institute for Biophysical Chemistry (MPIbpc) and the German Center for Neurodegenerative Diseases (DZNE) in Göttingen, together with their colleagues at the Polish Academy of Sciences in Warsaw and at the University of Warsaw, have rendered visible -- at atomic resolution -- how a protein progressively "loses its shape." In doing so, the researchers had pinned their hopes on low temperatures. "If a protein is slowly cooled down, its intermediate forms accumulate in larger quantities than in commonly used denaturation methods, such as heat, pressure, or urea. We hoped that these quantities would be sufficient to examine the intermediate forms with nuclear magnetic resonance (NMR) spectroscopy," said Markus Zweckstetter, head of the research groups "Protein Structure Determination using MNR" at the MPIbpc and "Structural Biology in Dementia" at the DZNE in Göttingen.

How a protein loses its shape

As research object, Zweckstetter's team chose a key protein for toxin production in Enterococcus faecalis, a pathogen frequently encountered in hospitals where it particularly jeopardizes patients with a weak immune system. But that is not the only reason why the so-called CylR2 protein is interesting. Some time ago, researchers working with Stefan Becker at the MPIbpc succeeded in elucidating its structure, which shows: Its three-dimensional shape makes CylR2 a particular promising candidate for the scientists' approach. "ClyR2 is a relatively small protein composed of two identical subunits. This gave us a great chance to be able to visualize the individual stages of its unfolding process in the test tube," explained the chemists Mariusz and Lukasz Jaremko.

Stefan Becker's group undertook the first step: to prepare a sufficient quantity of the protein in the laboratory. Subsequently, the two chemists cooled the protein successively from 25°C to -16°C and examined its intermediate forms with NMR spectroscopy. They achieved what they had hoped for: Their "film clip" shows at atomic resolution how the protein gradually unfolds. The structural biologist Markus Zweckstetter describes exactly what happens in this process: "We clearly see how the CylR2 protein ultimately splits into its two subunits. The individual subunit is initially relatively stable. With further cooling, the protein continues to unfold and at -16 °C it is extremely instable and dynamic. This instable protein form provides the seed for folding and can also be the "trigger" for misfolding." The scientist's findings may help to gain deeper insights into how proteins assume their spatial structure and why intermediate forms of certain proteins misfold in the event of illness.


Story Source:

The above story is based on materials provided by Max Planck Institute for Biophysical Chemistry. Note: Materials may be edited for content and length.


Journal Reference:

  1. Mariusz Jaremko, Łukasz Jaremko, Hai-Young Kim, Min-Kyu Cho, Charles D Schwieters, Karin Giller, Stefan Becker, Markus Zweckstetter. Cold denaturation of a protein dimer monitored at atomic resolution. Nature Chemical Biology, 2013; DOI: 10.1038/nchembio.1181

Cite This Page:

Max Planck Institute for Biophysical Chemistry. "Protein 'filmed' while unfolding at atomic resolution." ScienceDaily. ScienceDaily, 11 February 2013. <www.sciencedaily.com/releases/2013/02/130211090924.htm>.
Max Planck Institute for Biophysical Chemistry. (2013, February 11). Protein 'filmed' while unfolding at atomic resolution. ScienceDaily. Retrieved September 19, 2014 from www.sciencedaily.com/releases/2013/02/130211090924.htm
Max Planck Institute for Biophysical Chemistry. "Protein 'filmed' while unfolding at atomic resolution." ScienceDaily. www.sciencedaily.com/releases/2013/02/130211090924.htm (accessed September 19, 2014).

Share This



More Plants & Animals News

Friday, September 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) — Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) — The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) — A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
Powered by NewsLook.com
Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) — Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
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