The following news release is being issued today by the U.S. Department
of Energy's Brookhaven National Laboratory. An electronic version, with
pictures, can be viewed at:
http://www.bnl.gov/bnlweb/pubaf/pr/PR_display.asp?prID=05-33
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Number: 05-33
For release on: Monday, April 04, 2005
An Exceptionally Effective Lead-Detection Protein
Results may inspire new treatments for lead poisoning
Upton, NY -- Scientists from the U.S. Department of Energy's Brookhaven
National Laboratory and the University of Chicago have discovered that
a member of a well-known protein family is better at detecting lead
than any other known substance. Learning more about the protein's
structure and lead-detection mechanism, they say, may lead to new ways
to synthesize drugs or to develop treatments for lead poisoning, a
worldwide problem that, in the U.S. alone, inflicts irreversible
physical damage to half a million children each year.
"This protein can detect very few lead ions in a sea of other metals,"
said biologist Daniel (Niels) van der Lelie, one of the Brookhaven
scientists who participated in the study. "That's an unprecedented,
remarkable ability, and we are excited to learn how the protein does
it."
In fact, the results, published in the March 31, 2005, online version
of Angewandte Chemie International Edition, show that the protein is
more than one thousand times more likely to bind to lead than other
metals, such as mercury, zinc, or copper.
To determine this, the researchers used a method developed by one of
the paper's co-authors, University of Chicago chemist Chuan He. They
bind the protein to a short segment of double-stranded DNA that will
fluoresce (emit light) if the DNA strands are separated. With no lead
nearby, the two strands of the DNA double helix stay "zipped," and
there is no fluorescence. But when a common lead ion, known as
lead(II), binds to the protein, the DNA strands "unzip," releasing a
burst of ultraviolet light.
The scientists tested the protein's response to the presence of several
metals. Most elicited little to no reaction from the protein, producing
fluorescence barely above the constant background level. The lead(II)
ion, however, induced a large jump in the fluorescence intensity --
three times brighter than background.
"This fluorescence method converted the protein into an excellent
lead(II)-ion probe," said He. "It has the potential to be used for
rapid, on-the-spot lead detection in many situations, such as in
homes."
Van der Lelie, He, and their collaborators plan to further study the
structure of the protein, which may reveal why the molecule is so
selectively "interested" in lead ions. This information could be used
to design lead-poisoning treatment agents that would bind only to lead
ions in the body. Current treatments are not so selective, also
stripping away beneficial metals, such as iron and zinc, which results
in serious side effects.
The scientists will also attempt to optimize the DNA-probe method so
that the probe emits visible light. This would simplify detection and
increase the probe's practicality. The group will also apply similar
strategies to developing sensor systems for other metal ions.
This work was supported by the University of Chicago, the Searle
Scholars Program, the Burroughs Wellcome Fund Cross-Disciplinary
Training Program, and funds from Brookhaven's Laboratory Directed
Research and Development program.
One of the ten national laboratories overseen and primarily funded by
the Office of Science of the U.S. Department of Energy (DOE),
Brookhaven National Laboratory conducts research in the physical,
biomedical, and environmental sciences, as well as in energy
technologies and national security. Brookhaven Lab also builds and
operates major scientific facilities available to university, industry
and government researchers. Brookhaven is operated and managed for
DOE's Office of Science by Brookhaven Science Associates, a
limited-liability company founded by Stony Brook University, the
largest academic user of Laboratory facilities, and Battelle, a
nonprofit, applied science and technology organization. Visit
Brookhaven Lab's electronic newsroom for links, news archives,
graphics, and more: http://www.bnl.gov/newsroom.
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