Experimenters at Northeastern University and Argonne National Laboratory have developed a new technique for studying the vibrational properties of a protein at low frequencies.

The team of researchers, led by Northeastern University physics Prof. Tim Sage, found a way to measure low-frequency vibrations of iron-based heme molecules by using the X-ray Science Division 3-ID x-ray beamline at the U.S. Department of Energy Office of Science’s Advanced Photon Source (APS) at Argonne National Laboratory.
The new technique, called nuclear resonance vibrational spectroscopy (NRVS), will provide new information about the vibrational dynamics of the heme molecule. Hemes are most commonly recognized as a component of hemoglobin, which creates the red pigment in blood.

Sage’s research was featured as a cover story in the July 7, 2011 issue of Journal of Chemical Physics.

“What originally brought us to the APS was extending our investigations to lower frequencies where these vibrational motions not only are probes but actually participate in and drive the reactions that these molecules are involved in,” said Sage.

As former director of the APS, Northeastern’s Dean of Science J. Murray Gibson noted – “NRVS is a technique that takes full advantage of the unique properties of a high-energy x-ray synchrotron like APS, the brightest in the Western Hemisphere.  Tim’s work is a beautiful example of the power of NRVS to study the important dynamics of protein molecules.”

This technique allows the ultimate probe selectivity, while avoiding vibrational interference from other sources. “You can zoom in right on the iron, specifically looking at one atom out of thousands of surrounding atoms, surgically targeting those vibrations,” said Sage.

Researchers hope this technique will lead to a better understanding of the structure of molecules.

Heme molecules were the focus of this study, but the research team hopes to eventually use this technique to examine other proteins.