Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Neutron scattering explains how myoglobin can perform without water

02.08.2012
Understanding will help protein's potential application in biochemical gas sensors or in state-of-the-art wound dressing

Proteins do not need to be surrounded by water to carry out their vital biological functions, according to scientists from the Institut de Biologie Structurale (IBS) in Grenoble, the University of Bristol, the Australian National University, the Institut Laue Langevin and the Jülich Centre for Neutron Science.

In a new paper, published in the Journal of the American Chemical Society, the team used a state-of-the-art neutron scattering technique to demonstrate that when myoglobin, an oxygen-binding protein found in the muscle tissue of vertebrates, is enclosed in a sheath of surfactant molecules, it moves in the same way as when it is surrounded by water. These motions are essential if a protein is to perform its biological function, and their findings make proteins a viable material for use in new wound dressings or even as chemical gas sensors.

Water is the natural environment for soluble proteins and an integral part of their structures which allows them to carry out their specific function. It had been perceived for many years that proteins required water or another solvent in order to function. But in 2010, the Bristol team proved that by grafting polymer chains onto the protein surface, it was possible to produce solvent- and water-free myoglobin liquids that could still perform their biological roles. Scientists have now demonstrated that protein dynamics is the reason why.

Myoglobin is common to almost all mammals and responsible for the red colour of raw meat. Like all soluble proteins, its surface is covered with water molecules. In this study researchers wanted to assess whether the protein structure could still move and continue to bind oxygen if all the water was completely removed and replaced by synthetic molecules.

The team analysed three samples, a wet sample (the protein in water), a dry sample (the dehydrated protein) and a dry protein-polymer hybrid sample where the water molecules had been replaced by synthetically crafted polyethylene glycol-based polymer surfactant molecules. Using a technique called incoherent neutron scattering at the Institut Laue Langevin (ILL) in Grenoble, France, and at the Jülich Centre for Neutron Science at FRMII, Garching, Germany, the team was able to monitor the motions in the protein and in the polymer surfactant separately. This separation has been made possible by specific labelling, carried out in a dedicated deuteration laboratory at the ILL, by which either polymer or protein motions are masked by replacing hydrogen with its heavier isotope, deuterium.

What they found was that the myoglobin molecules surrounded by polymer moved just as well as the wet sample, and that the dry sample had very little mobility. Knowing that proteins can function outside of water opens them up to use in real life applications because it shows that there are other alternatives if water is unavailable. Examples of where they could be used include biochemical gas sensors, as myoglobin can bind carbon monoxide molecules.

Another potential application is in the development of new wound dressings, where the liquid protein could be applied either internally and externally to the wound to reduce healing time by supplying oxygen or other essential chemicals to the damaged tissue.

Adam Perriman of the University of Bristol's School of Chemistry said: "These discoveries have increased our fundamental understanding of proteins and how they behave, which could create many new opportunities for their application in industrial processing and in medical technologies. The fact that our proteins can happily perform their function outside of water, a substance generally thought to be vital for life, really drives home just how robust these biological nanomachines are."

Martin Weik of the Institut de Biologie Structurale explained: "Neutron scattering techniques are excellent for studying the dynamics of proteins and of their environment. The world-class neutron scattering facilities at the ILL and the FRM II allow us to analyse how proteins move, thus complementing the single snapshots of their structures provided by crystallography."

Earlier this month, Martin Weik and colleagues from the IBS, the ILL, the University of California, the Australian Institute of Science and Technology Organisation and the Jülich Centre for Neutron Science at FRMII, applied these techniques to an intrinsically disordered protein (IDP) called tau, to try and understand how its flexibility and its interactions with water differ from ordered proteins such as myoglobin.

They found that the coupling of the disordered tau protein with water motions was much tighter than for folded proteins. IDPs are of significant interest in a medical context because they can aggregate and cluster together to create the amyloid fibrils behind neuro-degenerative diseases such as Parkinson's and Alzheimer's. Whilst the ordered structure of folded proteins makes it possible to develop drugs that fit into the protein like a key in a lock, the conformational variability of an intrinsically disordered protein like tau makes it more difficult. A more in-depth understanding of their dynamics is required and the discovery of tight coupling with water motions is a significant step forward.

Hannah Johnson | EurekAlert!
Further information:
http://www.bristol.ac.uk

More articles from Life Sciences:

nachricht Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

NSF-supported researchers to present new results on hurricanes and other extreme events

19.07.2018 | Earth Sciences

Scientists uncover the role of a protein in production & survival of myelin-forming cells

19.07.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>