News: Scientists discover possible mechanism for creating 'handedness' in biological molecules
- From: "Robert Karl Stonjek" <rstonjek@xxxxxxxxxxxxxx>
- Date: Wed, 3 Dec 2008 01:36:54 -0500 (EST)
Scientists discover possible mechanism for creating 'handedness' in
biological molecules
(PhysOrg.com) --The basic molecules that make up all living things have a
predetermined chirality or "handedness," similar to the way people are
right- or left-handed. This chirality has a profound influence on the
chemistry and molecular interactions of living organisms. The creation of
chirality from the elementary building blocks of matter is one of the great
mysteries of the origin of life. Scientists at the U.S. Department of
Energy's Argonne National Laboratory have discovered a way to induce this
handedness in pre-biological molecules.
"Understanding how the molecules necessary for life originated is one of the
most basic scientific questions in biochemistry," said Argonne chemist
Richard Rosenberg. "Chirality plays a fundamental role in biological
processes, and researchers have been trying for years to discover the
mechanisms that led to this property."
Rosenberg used X-rays from the Advanced Photon Source to bombard chiral
molecules adsorbed on a magnetic substrate and X-ray photoelectron
spectroscopy to track changes in their molecular bonds.
He found that changing the magnetization direction in relation to the
high-intensity X-ray beam created an excess of one chirality over another.
Changing the magnetization direction reverses the spin polarization of the
secondary, or low-energy, electrons emitted from the substance.
Iron is a common element and is magnetic in many forms, and ionizing
radiation and magnetic fields are prevalent throughout the universe.
Based on the Argonne results, it is conceivable that chirality could have
been introduced by irradiation of molecules as they traveled through the
universe while adsorbed on a magnetized substrate in a dust cloud, meteor,
comet or on a primitive planet.
"Our study shows that spin-polarized secondary electrons interacting with
chiral molecules could produce a significant excess of a given chirality in
pre-biological molecules," Rosenberg said.
Argonne funded this research, which made use of a beamline at the Advanced
Photon Source, an advanced X-ray light source built and funded by the Office
of Basic Energy Sciences in the U.S. Department of Energy's Office of
Science and used for advanced energy and materials science research.
A paper on Rosenberg's work appeared in a recent issue of Physical Review
Letters.
Provided by Argonne National Laboratory
http://www.physorg.com/news147363159.html
Posted by
Robert Karl Stonjek
.
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