Argonne scientists use lasers to align molecules
Technique
could revolutionize human protein imaging
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ARGONNE, Ill. (May 13, 2008) – Protein crystallographers have only scratched
the surface of the human proteins important for drug interactions because
of difficulties crystallizing the molecules for synchrotron X-ray diffraction.
Now scientists at the U.S. Department of Energy's (DOE) Argonne National
Laboratory have devised a way to eliminate the need for crystallization by
using lasers to align large groups of molecules.
Funding for this research was provided by the U.S. Department of Energy, Office
of Science, Office of Basic
Energy Sciences. The mission of the Basic Energy Sciences program – a
multipurpose, scientific research effort – is to foster and support fundamental
research to expand the scientific foundations for new and improved energy
technologies and for understanding and mitigating the environmental impacts
of energy use. The portfolio supports work in the natural sciences, emphasizing
fundamental research in materials sciences, chemistry, geosciences, and
aspects of biosciences. |
"Strong laser fields can be used to control the behavior of atoms and
molecules," Argonne
Distinguished Fellow Linda Young said. "Using
X-rays, we can investigate their properties in a totally new way."
Crystallization allows scientists to create a periodic structure that will
strongly diffract in specific directions when bombarded with X-rays. From the
resulting diffraction pattern, scientists can construct a real-space image
of the crystal. However, without crystallization, when X-rays collide with
multiple, randomly oriented molecules, they diffract in different directions,
making it impossible to create a composite diffraction image, said Argonne
Physicist Robin Santra.
Some molecules, such as many involved with drug interaction, cannot be crystallized,
and imaging would require numerous samples to bombard in order to get a full
composite picture. Young's laser technique allows for millions of molecules
suspended in a gaseous state to be aligned so that, when bombarded with X-rays,
they all diffract in the same way. The resulting images are at atomic level
resolution and do not require crystallization.
"Understanding the structure of the approximately 1 million human proteins
that cannot be crystallized is perhaps the most important challenge facing
structural biology," Young said. "A method for structure determination
at atomic resolution without the need to crystallize would be revolutionary."
Young and her team have successfully aligned molecules using a laser, probed
the aligned ensemble with X-rays and shown theoretically that the technique
could be used for X-ray imaging – see E. R. Peterson et al., Applied
Physics Letters 92, 094106 (2008) – but they require a proposed upgrade to the
Advanced Photon Source facility located at Argonne before X-ray diffraction
can be done experimentally.
Funding for this research was provided by the U.S. Department of Energy, Office
of Science, Office of Basic
Energy Sciences. The mission of the Basic Energy
Sciences program – a multipurpose, scientific research effort – is to foster
and support fundamental research to expand the scientific foundations for new
and improved energy technologies and for understanding and mitigating the environmental
impacts of energy use. The portfolio supports work in the natural sciences,
emphasizing fundamental research in materials sciences, chemistry, geosciences,
and aspects of biosciences.
Argonne National Laboratory brings the world's brightest scientists and engineers
together to find exciting and creative new solutions to pressing national problems
in science and technology. The nation's first national laboratory, Argonne
conducts leading-edge basic and applied scientific research in virtually every
scientific discipline. Argonne researchers work closely with researchers from
hundreds of companies, universities, and federal, state and municipal agencies
to help them solve their specific problems, advance America 's scientific leadership
and prepare the nation for a better future. With employees from more than 60
nations, Argonne is managed by UChicago
Argonne, LLC for the U.S.
Department of Energy's Office
of Science.
For more information, please contact Brock Cooper (630/252-5565
or bcooper@anl.gov) at Argonne.
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