Study in Chemical Physics Letters details the use of terahertz spectroscopy and nanodroplets.
Scientists at the National Institute of Standards and Technology say that they have developed a way to view how biomolecules flex and bend in water. The technique is based on terahertz spectroscopy combined with nanoscale solution droplets made of soap-like molecules called micelles.
Researchers interested in how biomolecules such as amino acids and proteins operate have long had to make inferences from a series of x-ray-like still pictures of pure crystalline samples. The new method allows investigators to view previously concealed maneuverings of biomolecules in water.
The investigators say this study is an important first step toward using terahertz radiation for studying biomolecules, though the group admits more ambitious measurements on larger molecules such as small peptides, proteins, and DNA fragments will be more challenging.
To avoid the problem of room temperature water absorbing nearly all of the terahertz radiation, the team found a simple but realistic environment for the biomolecules that contained the least amount of water possible.
Using micelles as tiny test tubes, the team filled the hollow molecules with a small sample of water and the amino acid L-proline, a protein building block. Measurements validated their hypothesis that the micelles would provide an aqueous environment that allows the amino acid to flex and bend while limiting the absorption of the terahertz radiation by water. The terahertz measurements on this simple biomolecule compared well with expectations from other studies, further validating the technique.
“If we can get larger molecules in [the micelles], we can get a much better idea of how living molecules function,” points out Ted Heilweil, Ph.D., National Research Council postdoctoral fellow. “This will let us see the basic, most fundamental building blocks of life as they move.”
The article appears in the January 5 edition of Chemical Physics Letters.
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