Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Chemists make beds with soft landings

19.08.2008
Researchers create stable, highly pure helical peptide arrays

Bedsprings aren't often found in biology. Now, chemists have succeeded in making a layer of tiny protein coils attached to a surface, much like miniature bedsprings in a frame. This thin film made of stable and very pure helices can help researchers develop molecular electronics or solar cells, or to divine the biology of proteins.

Physical chemists at the Department of Energy's Pacific Northwest National Laboratory pulled off this design trick using a "soft-landing" technique that disperses the tiny protein coils onto a waiting surface. The small proteins called peptides are of a variety that normally take the shape of a coiled spring or helix in gas phase. The method used by PNNL's Julia Laskin and Peng Wang delivered ultra-pure helical peptides to the surface and trapped them there, they report in July 29 and will appear in print in an upcoming issue of Angewandte Chemie.

"Controlling the conformation of peptides is not easy," said Laskin. "Our previous studies showed that soft-landing can be used to prepare ultrapure peptide layers on substrates. The question we faced was, in addition to controlling purity, can we also control the structure of the molecules? We showed we could."

Researchers have been trying to make thin films of helical peptides for many years. Because the peptides line up in an orderly fashion, the overall chemical nature of the thin films make them useful for a variety of technological applications. They can be modified with light sensitive molecules and turned into components of solar cells; or designed to change shape when a current is applied for molecular electronics. Also, the helices themselves can be used to elicit cues about how proteins function.

After making the thin films out of generic peptides previously, Laskin and Wang wanted to use this method to make a film out of helical peptides, and compare it with a more common method called electrospray.

To do so, Laskin and Wang began with peptides made almost entirely of the amino acid alanine. Due to alanine's chemical nature, long chains of it naturally form so-called á helices. The researchers ended the alanine chain with the amino acid lysine, which stabilizes the helix and allows the coiled chain to be chemically attached to the surface.

Working with a specially designed mass-selected ion deposition instrument at DOE's Environmental Molecular Sciences Laboratory on the PNNL campus, they deposited the peptides on the support layer in one of two ways, starting either from a liquid form for electrospray or from a gaseous mixture for soft-landing. In each case, the chemists began with the peptides (either in liquid or gas), zapped them to give them a slight electrical charge and blew them onto the surface.

When the chemists examined the peptide shapes in the solution and the resulting thin film, they found, unexpectedly, that most of the peptides failed to form helices. Instead, the majority of peptides took on a flat shape known as a â sheet. The dearth of helices in liquid form surprised the researchers.

When the researchers next used soft-landing to form thin layers, they didn't know if the peptides would form helices before landing on the surface. "Because we were starting from something that wasn't á-helical in solution, we were a little pessimistic whether it would work at all," Wang said.

But work it did. Depositing the peptides with soft-landing, the chemists found that nearly all of them alighted as helices. In addition, they could chemically connect the helices to the surface using a related technique called reactive-landing. When the chemists treated the thin layer with sound waves to test how easily the peptides fell off or changed shape, they found that some loosely bound peptides fell off, but those remaining maintained their helical forms.

"They formed a nicely organized, beautiful layer," says Wang.

Next, the team would like to create thin peptide layers using different support surfaces and a different mix of peptide shapes, to learn how to control the design of the thin films precisely.

"We found an interesting pathway to conduct different types of chemical reactions between complex molecules and substrates that will potentially enable us to prepare materials that cannot be made by standard methods," said Laskin.

"We hope to conduct lots of chemistry on the thin films," said Laskin -- chemistry that will let them spring forward into understanding biology and developing new materials.

Reference: P. Wang and J. Laskin, Helical Peptide Arrays on Self-Assembled Monolayer Surfaces through Soft and Reactive Landing of Mass-Selected Ions, Angewandte Chemie, online July 29, 2008, DOI 10.1002/anie.200801366 (http://dx.doi.org/10.1002/anie.200801366).

This work was supported by PNNL discretionary funding and DOE's Office of Basic Energy Sciences, part of the Office of Science.

The Environmental Molecular Sciences Laboratory is a national scientific user facility sponsored by the Department of Energy's Office of Science, Biological and Environmental Research program that is located at Pacific Northwest National Laboratory. EMSL offers an open, collaborative environment for scientific discovery to researchers around the world. EMSL's technical experts and suite of custom and advanced instruments are unmatched. Its integrated computational and experimental capabilities enable researchers to realize fundamental scientific insights and create new technologies.

Pacific Northwest National Laboratory is a Department of Energy Office of Science national laboratory where interdisciplinary teams advance science and technology and deliver solutions to America's most intractable problems in energy, national security and the environment. PNNL employs 4,000 staff, has a $855 million annual budget, and has been managed by Ohio-based Battelle since the lab's inception in 1965.

Mary Beckman | EurekAlert!
Further information:
http://www.pnl.gov
http://dx.doi.org/10.1002/anie.200801366

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 >>>