Madison, Wisconsin
October 20, 2003
The
billions of proteins that compose life on Earth remain one of
the truly uncharted territories in the biological universe, due
mainly to the slow and arduous techniques their exploration
requires.
Now, a
research partnership between the
University of Wisconsin-Madison and a Japanese university
and company aims to develop a technology that may allow
scientists to map the shapes and structures of proteins more
easily than ever before. The advance promises to help unlock the
inner workings of hundreds or even thousands of proteins,
according to UW-Madison biochemistry professor John Markley,
leading to a better understanding of protein-based diseases, and
providing fundamental new information about the building blocks
of all living beings, from bacteria to plants to people.
An
agreement signed this week by the UW-Madison's Center for
Eukaryotic Structural Genomics (CESG), the university's patent
management agency the Wisconsin Alumni Research Foundation
(WARF), Ehime
University in Matsuyama, Japan, and the Japanese
biotechnology company Cell-Free Sciences of Yokohama, formalizes
an ongoing collaboration between these groups to refine a
powerful new system, created in Japan, for making the large
quantities of purified protein that biochemists need to solve
protein structures.
Under the
agreement, CESG will become the only "beta test" site in the
nation for the system, comparing its success rate and cost with
conventional methods of producing protein for structural
studies.
Spearheading the effort to expand the technology are principal
investigator and CESG director Markley and scientist Dmitriy
Vinarov. Markley's CESG pilot project, funded by the National
Institutes of Health Protein Structure Initiative (PSI), uses
the tools of nuclear magnetic resonance (NMR) spectroscopy and
X-ray crystallography to visualize the twists, folds and shapes
that form each protein's unique structure. If the new production
system works as well as the researchers anticipate, it could in
some cases make enough protein for NMR analysis virtually
overnight.
"Right now,
it typically takes a year to solve the structure of just one
protein and costs between $100,000 and $200,000," says Markley.
"What our group as well eight other PSI pilot projects around
the country have found is that protein production represents the
major bottleneck in solving structures more quickly and
inexpensively.
"This
technology will potentially open that bottleneck," he says,
allowing scientists to map the human "proteome" in the same way
they've mapped the human genome. Knowing the structure of
abnormal proteins, such as those implicated in Alzheimer's and
"mad cow" disease, could lead to new treatments for those
disorders. Scientists might also more easily engineer changes
into known proteins or protein fragments to create new
protein-based pharmaceuticals.
Currently,
large amounts of individual proteins are usually produced by
engineering a bacterium, such as E. coli, to produce a foreign
protein as part of its normal growth. But proteins from plants
and humans tend to take on abnormal structures when made by E.
coli, rendering them useless for structural analysis. As a
result, CESG's own state-of-the-art E. coli production system
currently works with only 11 percent of the proteins the Center
targets for structure determination.
To overcome
this problem, scientists have turned to "cell-free" systems,
such as the one developed in Japan. Studies conducted in Japan
and confirmed by Vinarov at UW-Madison suggest the new system
could work with up to 60 percent of CESG's target proteins.
Originally
developed by Professor Yaeta Endo of Ehime University and
reported in the Proceeding of the National Academy of Sciences
in 2000 and 2002, the technology harnesses the protein-producing
capacity of extracts made from the tiny plant embryos inside
wheat seeds. Although others had previously used the system,
Endo greatly increased its efficiency and stability by devising
an extract preparation protocol that included careful washing of
the embryos to remove natural inhibitors of protein synthesis
present inside the seed.
Endo, Ehime
University and Cell-Free Sciences - a biotech company launched
to commercialize the technology - have subsequently made the
advance the basis of a new robotic system that automates roughly
three dozen synthesis steps normally performed manually by
scientists. As part of the agreement, the robotic system will be
shipped to Markley's lab from Cell-Free Sciences in
mid-November. Markley hopes to have it up and running by year's
end.
"We've
already demonstrated we can use the wheat germ extract by hand
to produce enough protein for structural analysis," says
Vinarov. "The automation will now allow us to evaluate this
technology as a possible high-throughput method of protein
production."
"Although
it still needs validation," adds Markley. "This system could
become the new platform for large-scale, cell-free protein
synthesis. We're very pleased this collaboration is moving
forward." |