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 Study shines light on brain cells that coordinate movement
26.06.2017 | University of Washington Health Sciences/UW Medicine

nachricht New insight into a central biological dogma on ion transport
26.06.2017 | Aarhus University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Study shines light on brain cells that coordinate movement

26.06.2017 | Life Sciences

Smooth propagation of spin waves using gold

26.06.2017 | Physics and Astronomy

Switchable DNA mini-machines store information

26.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>