Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The assembly of protein strands into fibrils

12.04.2010
The Atomic Force Microscope depicts on its screen the few nanometer thick and few micrometer long fibers as white flexible sticks, crisscrossing the surface on which they are deposited. The very peculiar property of these proteins lies in fact that they can self assemble into complex ribbon-like twisted fibers.

Researchers at ETH Zürich, EPF Lausanne and University of Fribourg have teamed up to take Atomic Force Microscopy images of the fibers and to analyze them using concepts from polymer physics and theoretical modeling.

This combination of expertise has lead them to propose a set of general rules governing the assembly of filaments into thicker and twisted ribbon like fibers. Their results are published in the current issue of the scientific journal "Nature Nanotechnology".

"The model that we propose is extremely precise in its predictions", says Raffaele Mezzenga, Professor of Food and Soft Materials Sciences at the ETH Zürich. "Up to now there was no such exact and general model for the formation of Amyloid fibers", continues Giovanni Dietler, Professor of Physics of Living Matter, at the EPF Lausanne.

The structure of the Amyloid fibers as it was unveiled by the experiments, surprised the researchers. Single proteins build the long filaments and subsequently the filaments assemble side by side to form the ribbon-like twisted fibers.

Mezzenga explains that the ribbon-like structure is the logic consequence of the strong charge carried by the building blocks of the fibers. In fact, the single proteins feel a strong mutual repulsion preventing them to pack and the ribbon structure is the only one that permits to limit this repulsion. Presently one missing information in the present model, is the exact nature of the short range attraction between the building blocks that drives in the first place the assembly among the protein filaments. Scientists agree that along the filaments there are charge-less domains of hydrophobic character (water repellant) that are the source of the short-range attraction. So there is a balance between attractive and repulsive interactions and the results is the ribbon like twisted conformation.

Self-organizing proteins are common in living matter and they are found in large aggregates for example in blood coagulation. Spherical like proteins are used in food industry as emulsifiers, gelling and foaming agents and in vitro they form Amyloid like structures. These latter fibers have properties (elasticity, solubility, etc) favorable for food texturing or to produce special structures. The milk protein beta-lactoglubulin studied by Mezzenga and his colleagues is at the beginning spherical and by a heat treatment accompanied by acid environment it aggregates into the filamentous structures. Beta-lactoglobulin is an important component of the milk serum and therefore very relevant for food industry.

The knowledge gained by the scientists on this food protein can potentially benefit medical sciences. In fact Amyloid-like fibers appear in humans affected by neurodegenerative diseases, like Alzheimer- or Creutzfeldt-Jakob disease. These human fibers, although made out of a very different proteins, are also ribbon-like and twisted and their assembly into long aggregates is presently under intense scrutiny. The model proposed by the team could also help to understand the genesis and development of theses diseases.

Giovanni Dietler | EurekAlert!
Further information:
http://www.epfl.ch

More articles from Life Sciences:

nachricht Scientists spin artificial silk from whey protein
24.01.2017 | Deutsches Elektronen-Synchrotron DESY

nachricht Choreographing the microRNA-target dance
24.01.2017 | UT Southwestern Medical Center

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Scientists spin artificial silk from whey protein

X-ray study throws light on key process for production

A Swedish-German team of researchers has cleared up a key process for the artificial production of silk. With the help of the intense X-rays from DESY's...

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Breaking the optical bandwidth record of stable pulsed lasers

24.01.2017 | Physics and Astronomy

Choreographing the microRNA-target dance

24.01.2017 | Life Sciences

Spanish scientists create a 3-D bioprinter to print human skin

24.01.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>