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 Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute

nachricht Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>