A new tool to reveal structure of proteins

Mar 19, 2012 by Pam Frost Gorder

A new method to reveal the structure of proteins could help researchers understand biological molecules – both those involved in causing disease and those performing critical functions in healthy cells.

For roughly a decade, a technique called solid state nuclear magnetic resonance (NMR) spectroscopy has allowed researchers to detect the arrangements of atoms in proteins that defy study by traditional laboratory tools such as X-ray crystallography. But translating solid state NMR data into an actual 3D protein structures has always been difficult.

In the current online edition of Nature Chemistry, Christopher Jaroniec, associate professor of chemistry at Ohio State University, and his colleagues describe a new NMR method that uses paramagnetic tags to help visualize the shape of protein molecules.

"Structural information about is critical to understanding their function," Jaroniec said. "Our new method promises to be a valuable addition to the NMR toolbox for rapidly determining the structures of protein systems which defy analysis with other techniques."

Such protein systems include amyloids, which are fibrous clusters of proteins found in diseased cells, and associated with the development of certain neurological diseases in humans.

"Although for the purposes of the paper we tested the method on a small model protein, the applications are actually quite general," Jaroniec added. "We expect that the method will work on many larger and more challenging proteins."

Protein molecules are made up of long chains of amino acids folded and wrapped around themselves, like tangled spaghetti. Every type of protein folds into its own unique pattern, and the pattern determines its function in the body. Understanding why a protein folds the way it does could give scientists clues on how to destroy a protein, or alter its function.

To test their method, the researchers chose a protein called GB1, a common protein found in Streptococcus bacteria. GB1 has been much studied by scientists, so the structure is already known. They engineered a form of the protein in which certain amino acids along the chain were replaced with a different amino acid – cysteine – and created the right chemical conditions for yet another tag – one containing an atom of copper – to stick to the cysteine. The amino acid-copper tags are known as "paramagnetic" molecules, and they significantly influence the signals emitted by the different protein atoms in the magnetic field of an NMR instrument.

The researchers were able to determine the locations of the protein atoms relative to the paramagnetic tags, and use this information to calculate the folded shape of the GB1 .

Explore further: Biosensor may improve clinical diagnosis of influenza A

Related Stories

New technique enables study of 'challenging' proteins

Nov 14, 2011

Researchers from Hull, Bristol and Frankfurt have shown that a new technique for identifying molecular structure can be used effectively on small samples of biological proteins, particularly proteins that are targeted for ...

Chemists develop faster, more efficient protein labeling

Feb 05, 2012

North Carolina State University researchers have created specially engineered mammalian cells to provide a new "chemical handle" which will enable researchers to label proteins of interest more efficiently, without disrupting ...

Recommended for you

Devices designed to identify pathogens in food

19 hours ago

Researchers at the National Polytechnic Institute (IPN) in Mexico have developed a technology capable of identifying pathogens in food and beverages. This technique could work in the restaurant industry as ...

Biosensor may improve clinical diagnosis of influenza A

20 hours ago

Sensors based on special sound waves known as surface acoustic waves (SAWs) are capable of detecting tiny amounts of antigens of Influenza A viruses. Developed by A*STAR researchers, the biosensors have the ...

New chip makes testing for antibiotic-resistant bacteria faster, easier

May 26, 2015

We live in fear of 'superbugs': infectious bacteria that don't respond to treatment by antibiotics, and can turn a routine hospital stay into a nightmare. A 2015 Health Canada report estimates that superbugs have already cost Canadians $1 billion, and are a "serious and growing issue." Each year two million people in the U.S. contract antibiotic-re ...

Use your smartphone for biosensing

May 26, 2015

An Australian research team has shown that smartphones can be reconfigured as cost-effective, portable bioanalytical devices, with details reported in the latest edition of the Open Access Journal 'Sensors'.

Faster, portable microbial analysis in the field

May 25, 2015

Until recently, it took hours – sometimes days – to analyze biological samples after they were frozen in the field and brought back to the laboratory. But now there is a faster, cheaper and smaller way ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.