Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists develop new color-coded test for protein folding

29.03.2005


Every protein--from albumin to testosterone--is folded into a unique, three-dimensional shape that allows it to function properly. Now Stanford University scientists have developed a simple test that instantly changes color when a protein molecule attached to a gold nanoparticle folds or unfolds. The new technique, which works on the same principle as ordinary pH tests that measure the acidity of water, is described in the March 2005 issue of the journal Chemistry and Biology.



"What we’ve developed is a simple and inexpensive sensor for determining when a protein changes its conformation," said study co-author Richard N. Zare, the Marguerite Blake Wilbur Professor in Natural Science in Stanford’s Department of Chemistry. According to Zare, the new sensor may eventually provide biomedical researchers a fast, affordable method for detecting antibodies and other disease-related proteins. Acid and base

In their experiment, Zare, postdoctoral fellow Soonwoo Chah and graduate student Matthew R. Hammond created a liquid solution containing nano-sized particles of gold saturated with a protein called cytochrome c. "We chose gold nanoparticles because they are simple to prepare, easy to control and cost effective," the authors wrote. "To the best of our knowledge, however, gold nanoparticles have not been previously used to investigate the folding and unfolding of proteins."


The initial batch of gold-cytochrome solution had a rosy red hue and a pH value of 10--about the same as an over-the-counter heartburn medication. But when drops of hydrochloric acid were added, the solution began to change color, turning purple when the pH reached 5.8 and light blue at pH 4, which is close to the acidity of wine. Lab analysis revealed that additional hydrochloric acid was causing the cytochrome c molecules to unfold. As a result, gold nanoparticles coated with cytochrome c began clumping together--a process that caused the solution to quickly change from red to blue as the acidity increased.

The researchers were surprised to discover that, when the pH was raised from 4 to 10, the blue solution turned reddish once again--a strong indication that some cytochrome c molecules had refolded into their original three-dimensional shape. In fact, the experiment showed that, when attached to gold film, cytochrome c can fold, unfold and refold countless times depending on the acidity of the solution, thus making it an ideal tool for detecting conformational changes in proteins.

"While we’re not ready to mass-produce this technology, we believe it will eventually be useful for testing other, more complicated proteins," Zare said, noting that a gold nanoparticle sensor could turn out to be a quick and inexpensive way for doctors to identify antibodies and other signs of infection in the blood stream. Over the next few months, he and his colleagues plan to re-do the experiment using other protein molecules.

Mark Shwartz | EurekAlert!
Further information:
http://www.stanford.edu

More articles from Life Sciences:

nachricht Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery
20.01.2017 | GSI Helmholtzzentrum für Schwerionenforschung GmbH

nachricht Seeking structure with metagenome sequences
20.01.2017 | DOE/Joint Genome Institute

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

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

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>