Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Protein fishing in America: The movie

27.08.2004


Experiment proves that ’fly-fishing mechanism’ theory of protein-to-protein communication holds water



Proteins pass messages to other proteins much like fly-fishermen flicker their lines against water, or so a current leading theory holds. The repeated weak slapping of protein surfaces against one-another is the critical first step in a chain of events that rule all subsequent cellular behavior.

But this vital exchange between single molecules has defied direct observation because that line-flicking and message-passing happen randomly at such a small scale.


A Pacific Northwest National Laboratory team led by H. Peter Lu, using a technique called single-molecule photon stamping spectroscopy, has now observed real-time interactions of single proteins. Their experimental evidence, reported Thursday at the 228th national meeting of the American Chemical Society, supports the fly-fishing theory of protein communication.

"In the past five years, the field of protein-protein interaction dynamics has exploded," said Lu, a staff scientist at the Department of Energy laboratory in Richland, Wash. "Measurements to date have been snapshots of proteins. But to do dynamic measurements, to capture proteins in motion, this is unique."

Techniques such as nuclear magnetic resonance and x-ray crystallography reveal structural details about proteins and positions of their atoms at a particular time in space. They provide structural reference points, but to contrive interactions, many images have to be gathered at different times, events averaged out and a narrative flow imposed. The effect is akin to cutting a cartoon into a thousand frames tossing the pieces from the ceiling like confetti, then gathering them off the floor and reassembling them. Try making sense of that.

"It’s not an observation in real time," Lu said. "You’re measuring many proteins at a time, and you get information about two states and two states only: binding or not binding. How the binding and not binding are linked is hidden information." Lu’s single-molecule spectroscopy technique gathers and analyzes photons emitted as single proteins interact. This raw data may not produce what we would think of as a motion picture, but for Lu it is just as good. It enables him to construct--in true sequence and in real time--the position and continuous motion of the single molecules for the millisecond they flip-flop against each other.

So far, Lu’s team has looked at two different sets of proteins selected their importance in intracellular signaling--one called Cdc42 that activates with a protein known as WASP and calmodulin, a regulatory protein important in cells that depend on calcium for cell signaling, that can bind with various protein species.

Lu’s group has assembled an elaborate instrument at PNNL’s W.R. Wiley Environmental Molecular Sciences Laboratory. In the instrument, fluorescent-dye-tagged proteins are embedded in a gel and probed by a continuous-beam, or ultrafast, laser. The protein fluorescence fluctuates when molecules interact with one-another. The light emissions and fluctuations from the laser-excited molecules are captured and measured by an inverted fluorescence microscope across a field of about 250 nanometers; individual photons are directed toward a device called a photon-stamping detector that yields key information on each detected photon. "The detection is highly sensitive and precise," Lu said. "One molecule doesn’t have many photons give out. We need to capture as many photo-physical properties as we possibly can."

On this project, Lu’s group collaborated with molecular biologists Klaus Hahn from the Scripps Research Institute and Thomas Squier from Pacific Northwest National Laboratory.

Bill Cannon | EurekAlert!
Further information:
http://www.pnl.gov

More articles from Life Sciences:

nachricht Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory

nachricht How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>