Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

X-Ray Laser Reveals How Bacterial Protein Morphs in Response to Light

08.12.2014

A Series of Super-Sharp Snapshots Demonstrates a New Tool for Tracking Life's Chemistry

Human biology is a massive collection of chemical reactions, from the intricate signaling network that powers our brain activity to the body’s immune response to viruses and the way our eyes adjust to sunlight. All involve proteins, known as the molecules of life; and scientists have been steadily moving toward their ultimate goal of following these life-essential reactions step by step in real time, at the scale of atoms and electrons.


SLAC National Accelerator Laboratory

This illustration depicts an experiment at SLAC that revealed how a protein from photosynthetic bacteria changes shape in response to light. Samples of the crystallized protein (right), called photoactive yellow protein or PYP, were jetted into the path of SLAC's LCLS X-ray laser beam (fiery beam from bottom left). The crystallized proteins had been exposed to blue light (coming from left) to trigger shape changes. Diffraction patterns created when the X-ray laser hit the crystals allowed scientists to recreate the 3-D structure of the protein (center) and determine how light exposure changes its shape.

Now, researchers have captured the highest-resolution snapshots ever taken with an X-ray laser that show changes in a protein’s structure over time, revealing how a key protein in a photosynthetic bacterium changes shape when hit by light. They achieved a resolution of 1.6 angstroms, equivalent to the radius of a single tin atom.

"These results establish that we can use this same method with all kinds of biological molecules, including medically and pharmaceutically important proteins," said Marius Schmidt, a biophysicist at the University of Wisconsin-Milwaukee who led the experiment at the Department of Energy’s SLAC National Accelerator Laboratory. There is particular interest in exploring the fastest steps of chemical reactions driven by enzymes -- proteins that act as the body's natural catalysts, he said: "We are on the verge of opening up a whole new unexplored territory in biology, where we can study small but important reactions at ultrafast timescales.”

The results, detailed in a report published online Dec. 4 in Science, have exciting implications for research on some of the most pressing challenges in life sciences, which include understanding biology at its smallest scale and making movies that show biological molecules in motion.

A New Way to Study Shape-shifting Proteins

The experiment took place at SLAC’s Linac Coherent Light Source (LCLS), a DOE Office of Science User Facility. LCLS’s X-ray laser pulses, which are about a billion times brighter than X-rays from synchrotrons, allowed researchers to see atomic-scale details of how the bacterial protein changes within millionths of a second after it’s exposed to light.

"This experiment marks the first time LCLS has been used to directly observe a protein’s structural change as it happens. It opens the door to reaching even faster time scales," said Sébastien Boutet, a SLAC staff scientist who oversees the experimental station used in the study. LCLS's pulses, measured in quadrillionths of a second, work like a super-speed camera to record ultrafast changes, and snapshots taken at different points in time can be compiled into detailed movies.

The protein the researchers studied, found in purple bacteria and known as PYP for "photoactive yellow protein," functions much like a bacterial eye in sensing blue light. The mechanism is very similar to that of other receptors in biology, including receptors in the human eye. "Though the chemicals are different, it's the same kind of reaction," said Schmidt, who has studied PYP since 2001. Proving the technique works with a well-studied protein like PYP sets the stage to study more complex and biologically important molecules at LCLS, he said.

Chemistry on the Fly

In the LCLS experiment, researchers prepared crystallized samples of the protein, and exposed the crystals, each about 2 millionths of a meter long, to blue laser light before jetting them into the LCLS X-ray beam.

The X-rays produced patterns as they struck the crystals, which were used to reconstruct the 3-D structures of the proteins. Researchers compared the structures of the proteins that had been exposed to light to those that had not to identify light-induced structural changes.

"In the future we plan to study all sorts of enzymes and other proteins using this same technique," Schmidt said. "This study shows that the molecular details of life’s chemistry can be followed using X-ray laser crystallography, which puts some of biology’s most sought-after goals within reach.”

Researchers from the University of Wisconsin-Milwaukee and SLAC were joined by researchers from Arizona State University; Lawrence Livermore National Laboratory; University of Hamburg and DESY in Hamburg, Germany; State University of New York, Buffalo; University of Chicago; and Imperial College in London. The work was supported by the National Science Foundation, National Institutes of Health and Lawrence Livermore National Laboratory.

SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, Calif., SLAC is operated by Stanford University for the U.S. Department of Energy's Office of Science. For more information, please visit slac.stanford.edu.

SLAC National Accelerator Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

Contact Information
Andrew Gordon
External Communications Manager
agordon@slac.stanford.edu
Phone: 650-926-2282
Mobile: 510-325-9303

Andrew Gordon | newswise

More articles from Life Sciences:

nachricht What the world's tiniest 'monster truck' reveals
23.08.2017 | American Chemical Society

nachricht Treating arthritis with algae
23.08.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Researchers devise microreactor to study formation of methane hydrate

23.08.2017 | Materials Sciences

ShAPEing the future of magnesium car parts

23.08.2017 | Automotive Engineering

New insights into the world of trypanosomes

23.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>