Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Researchers Solve Complex Problem in Membrane Biochemistry Through Study of Amino Acids

After years of experimentation, researchers at the University of Arkansas have solved a complex, decades-old problem in membrane biochemistry. The consequence of their work will give scientists more information about the function and structure of proteins, the workhorses within the cells of the human body.

“Historically, lysine and arginine, both basic amino acids, were considered to have very similar properties and therefore to be essentially interchangeable,” said Denise Greathouse, a research associate professor in the department of chemistry and biochemistry. “Our results demonstrate that despite their similarities, the differences in their behavior in membrane environments provide important clues for understanding membrane protein function.”

The findings, which appear in the January issue of the journal Proceedings of the National Academy of Sciences, address long-standing questions in the study of protein structure and function and help explain how charged amino acids are able to modulate the behavior of proteins in cellular membranes.

Greathouse, former doctoral students Nicholas Gleason and Vitaly Vostrikov, and Roger Koeppe II, Distinguished Professor of chemistry and biochemistry, wrote the article, “Buried lysine, but not arginine, titrates and alters transmembrane helix tilt.”

Proteins do nearly all the work in the cells of our bodies, ranging from brain function and nerve transmission to metabolic energy production and muscular contraction. Moreover, many diseases are associated with defects in protein function. Future advances in the diagnosis and treatment of human disease will depend upon better understanding of the thousands of proteins that are encoded within the genomes of humans and human pathogens.

The structure and function of membrane proteins both play a crucial role in cell signaling and the regulation of biological function. The authors developed experimental methods that determine how lysine and arginine interact in the lipid bilayer membrane environment. In the last 10 years there have been computational predictions of the behavior of lysine and arginine in the membrane but not methods to test those predictions.

“It is the first measurement of its type, its complexity makes it an elegant method, and it opens the door for other people to apply these methods on biologically important problems,” Koeppe said. “There is a lot of interest in trying to understand what’s going on in these membranes, especially with protein molecules that carry particular electric charges. Unless we can understand it at the fundamental level, then we can’t extrapolate it to the nervous system. We’re trying to develop foundational knowledge that is needed to understand the nervous system.

“We’re excited about this study because it makes available knowledge that other researchers can use,” he said. “Those making the computer predictions can refine their methods and make better predictions because they know that they were able to reproduce some of our results.”

Lysine and arginine are ionizable, which means they can have a positive electric charge. The research team created a framework for experimentation that uses magnetic resonance imaging to measure whether the groups remain charged or become uncharged as the acidity or the pH of the environment is changed. To make their procedure work, the scientists synthesized peptides, which are chemical compounds consisting of several or more linked amino acids. To enable the magnetic resonance experiments, some of the hydrogen atoms in the peptides were replaced with deuterium, a heavy isotope of hydrogen.

“We’ve spent about 15 years doing this,” Koeppe said. “We developed first- and second-generation families of model peptides, and we examine them in model lipid membranes in order to understand the properties of real cell membranes and real cell proteins. This is at a molecular level. We are not even up to the cell yet.”

Vostrikov and Gleason earned their doctorates in 2011 and 2012, respectively. Vostrikov is a postdoctoral fellow at the University of Minnesota and Gleason teaches chemistry at Shiloh Christian School in Springdale.

The National Science Foundation provided the grant for the experiments described in the Proceedings of the National Academy of Sciences. The National Institutes of Health provided the financial support for the early stages of development of the peptide framework and for the facilities.

The research was performed in the U of A’s Center for Protein Structure and Function, which was established in 2000 in the J. William Fulbright College of Arts and Sciences to develop a detailed understanding of the structure and function of proteins that could lead to improved treatments of human disease. Center scientists study proteins involved in cancer, heart disease, osteoporosis, the flu and other diseases and conditions.


Roger Koeppe II, Distinguished Professor, chemistry and biochemistr
J. William Fulbright College of Arts and Sciences

Roger Koeppe | Newswise
Further information:

More articles from Life Sciences:

nachricht Atom-Sized Craters Make a Catalyst Much More Active
30.11.2015 | SLAC National Accelerator Laboratory

nachricht Hydra Can Modify Its Genetic Program
30.11.2015 | Université de Genève (University of Geneva)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: How Cells in the Developing Ear ‘Practice’ Hearing

Before the fluid of the middle ear drains and sound waves penetrate for the first time, the inner ear cells of newborn rodents practice for their big debut. Researchers at Johns Hopkins report they have figured out the molecular chain of events that enables the cells to make “sounds” on their own, essentially “practicing” their ability to process sounds in the world around them.

The researchers, who describe their experiments in the Dec. 3 edition of the journal Cell, show how hair cells in the inner ear can be activated in the absence...

Im Focus: Climate study finds evidence of global shift in the 1980s

Planet Earth experienced a global climate shift in the late 1980s on an unprecedented scale, fuelled by anthropogenic warming and a volcanic eruption, according to new research published this week.

Scientists say that a major step change, or ‘regime shift’, in the Earth’s biophysical systems, from the upper atmosphere to the depths of the ocean and from...

Im Focus: Innovative Photovoltaics – from the Lab to the Façade

Fraunhofer ISE Demonstrates New Cell and Module Technologies on its Outer Building Façade

The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...

Im Focus: Lactate for Brain Energy

Nerve cells cover their high energy demand with glucose and lactate. Scientists of the University of Zurich now provide new support for this. They show for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells. With this study they were able to confirm a 20-year old hypothesis.

In comparison to other organs, the human brain has the highest energy requirements. The supply of energy for nerve cells and the particular role of lactic acid...

Im Focus: Laser process simulation available as app for first time

In laser material processing, the simulation of processes has made great strides over the past few years. Today, the software can predict relatively well what will happen on the workpiece. Unfortunately, it is also highly complex and requires a lot of computing time. Thanks to clever simplification, experts from Fraunhofer ILT are now able to offer the first-ever simulation software that calculates processes in real time and also runs on tablet computers and smartphones. The fast software enables users to do without expensive experiments and to find optimum process parameters even more effectively.

Before now, the reliable simulation of laser processes was a job for experts. Armed with sophisticated software packages and after many hours on computer...

All Focus news of the innovation-report >>>



Event News

Urbanisation and migration from rural areas challenging agriculture in Eastern Europe

30.11.2015 | Event News

Fraunhofer’s Urban Futures Conference: 2 days in the city of the future

25.11.2015 | Event News

Gluten oder nicht Gluten? Überempfindlichkeit auf Weizen kann unterschiedliche Ursachen haben

17.11.2015 | Event News

Latest News

Teamplay IT solution enables more efficient use of protocols

30.11.2015 | Trade Fair News

Greater efficiency and potentially reduced costs with new MRI applications

30.11.2015 | Trade Fair News

Modular syngo.plaza as a comprehensive solution – even for enterprise radiology

30.11.2015 | Trade Fair News

More VideoLinks >>>