Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scripps research study reveals structural dynamics of single prion molecules

14.02.2007
New techniques paint clearer picture of amyloid formation associated with protein-based inheritance and neurodegenerative diseases such as mad cow, Alzheimer's

The new findings, which are being published the week of February 12 in an online edition of the Proceedings of the National Academy of Sciences, offer significant insights into normal folding mechanisms as well as those that lead to abnormal amyloid fibril conversion. The new insights may lead to the discovery of novel therapeutic targets for neurodegenerative diseases.

Intriguingly, certain prions and amyloids can play beneficial roles. The subject of the new study, Sup35, enables protein-based inheritance in yeast. When this prion protein misfolds, it converts into self-perpetuating amyloid fibrils, thus altering its function in an inheritable manner. The research team used a combination of advanced biophysical methods to investigate these processes.

"By focusing on single unfolded prions, we were able to define the dynamics of two distinct regions or domains that determine conversion dynamics," said Ashok A. Deniz, a Scripps Research scientist who led the study. "Our research techniques can now be used to probe the structures of other amyloidogenic proteins. This could prove important in understanding the basic biology of amyloid formation, as well as in designing strategies against misfolding diseases."

... more about:
»Amyloid »Dynamic »Prion »fluorescence »intermediate

Interestingly, the new study revealed that yeast prion protein Sup35 lacks a specific, static structure in its native collapsed state. Instead, the compact protein fluctuates among several different structures before forming intermediate shapes during the amyloid assembly process.

The intermediate stages of the process are critically important, Deniz noted: "No single native unfolded protein is capable of initiating the amyloid cascade because of this constant shape-shifting. To start the amyloid conversion process, it has to first convert to an intermediate species, consisting of multiple protein molecules. This insight may be important to finding potential new therapeutic targets for disease-causing amyloids."

To define the dynamic structural details of individual prions, Deniz and his colleagues employed several novel technologies including single-molecule fluorescence resonance energy transfer (SM-FRET) and fluorescence correlation spectroscopy (FCS).

Fluorescence resonance energy transfer is a highly sensitive tool used to measure molecular structure and dynamics such as in single proteins at the angstrom level, a measurement unit used to define molecular distances (a 10th of a millionth of a millimeter). Fluorescence correlation spectroscopy is a high resolution technique that measures time fluctuations in fluorescent emissions from tagged proteins, which provided information about changes in shape of Sup35 taking place on the nanosecond timescale (billionths of seconds).

A third technology, single molecule fluorescence coincidence, was used in an unusual way-to prove that the protein species under scrutiny were not oligomeric (consisting of multiple proteins in an aggregate). The technology, based on measuring fluorescence bursts from individual tagged proteins, enabled the scientists to determine that the proteins being studied were, in fact, single monomers and not aggregates.

Deniz said that future work with yeast prion mutants might resolve some of the questions that remain unanswered. "Our laboratory has spent a great deal of time in improving these techniques, and we have used them to uncover some very intriguing information about this particular monomer," he said. "This combination of techniques can now be used to study other amyloidogenic proteins, including prions, particularly small assemblies and intermediate stages of the aggregation process. These are currently considered the most toxic forms of amyloid-disease associated proteins."

While mammalian prion proteins are different from those of yeast in their amino acid sequence, they do share some basic features, including their ability to catalyze the conversion to amyloid fibers. Some studies suggest that prions may also play key roles in certain critical processes such as long-term memory. Other authors of the study, A Natively Unfolded Yeast Prion Monomer Adopts An Ensemble of Collapsed and Rapidly Fluctuating Structures, are Samrat Mukhopadhyay and Edward A. Lemke of The Scripps Research Institute; and Susan Lindquist and Rajaraman Krishnan of the Whitehead Institute for Biomedical Research.

Marisela Chevez | EurekAlert!
Further information:
http://www.scripps.edu

Further reports about: Amyloid Dynamic Prion fluorescence intermediate

More articles from Life Sciences:

nachricht The birth of a new protein
20.10.2017 | University of Arizona

nachricht Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>