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JAPAN NANONET BULLETIN
-- 27th Issue -- September 16, 2004
Nanotechnology Researchers Network Center of Japan
Ministry of Education, Culture, Sports, Science and Technology (MEXT)
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IN THIS ISSUE
Nanonet Interview:
Masasuke YOSHIDA, Professor, Chemical Resources Laboratory, Tokyo
Institute of Technology
Young Researchers' Introduction:
Minoru OSADA, Senior Researcher, Advanced Materials Laboratory,
National Institute for Materials Science
-- NANO CALENDAR --
For information on nanotechnology related symposiums and conferences
held in the world,
http://www.nanonet.go.jp/english/calendar/
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NANONET INTERVIEW
Mystery behind bioenergy
--Proving the rotation of ATP synthase--
(Issued in Japanese: July 1, 2003)
Masasuke YOSHIDA, Professor, Chemical Resources Laboratory, Tokyo
Institute of Technology
"Living organisms do not favor rotation." It was surprising that Prof.
Yoshida who has proved the rotation of ATP (adenosine triphosphate)
synthase said that. "There are no living organisms with wheels. Isn't
that interesting?" says Prof. Yoshida.
ATP is a small molecule with the molecular weight of over 500. When
ATP turns into ADP (adenosine diphosphate) and inorganic phosphate
(Pi), it generates large energy of 7.5kcal per mole. Nearly all the
bioenergy is supplied by the ATP hydrolysis. However, there are only
10 to 20g of ATP in the human body. It cannot be conserved in the
body; therefore, the human body produces and consumes roughly the same
amount of ATP as his or her own weight in a day.
ATP plays such an important role for vital activity, and yet the
research on ATP synthase had not progressed. When Prof. Paul Boyer
advocated the rotation of ATP synthase 20 years ago, nobody listened
to him. It was 1994 when things turned around. Dr. John Walker
clarified the three-dimensional structure of ATP synthase. When Prof.
Yoshida saw the stalk at the center of a spherical hexamer, he was
shocked by the possibility of its rotation because he had not believed
the ATP synthase would rotate. And then, he decided to do the
experiments to prove the ATP synthase surely rotates.
It was difficult to prove it because the ATP synthase was too small to
observe with an optical microscope. So, Prof. Yoshida fixed the only
10nm-diameter hexamer surrounding the stalk with fluorescently labeled
1 micrometer-length actin filaments on the coverslip, and succeeded in
visualization and videotaping the rotation of ATP synthase. "Everyone
was surprised including myself because the primitive enzyme in every
living organism rotated. It was believed that living organisms did not
favor rotation." From the experiment, he has found out that ATP
synthase rotates the actin filaments at a high speed of 8 revolutions
per second. According to his calculation, it rotates with nearly
perfect energy efficiency.
The 1997 Nobel Prize went to Prof. Jens Skou for his discovery of an
ion-transporting enzyme and Prof. Paul Boyer and Dr. John Walker for
elucidation of the enzymatic mechanism underlying the synthesis of ATP.
The image of the rotation of ATP synthase was played in the
preliminary review board and it made their receiving the Nobel Prizes
definite. Prof. Yoshida was thought to share the Nobel Prize,
unfortunately, he missed receiving. He said, "The Nobel Prize is for
the persons who proposed a very original idea, persisted and prevailed.
Boyer deserved it."
What Prof. Yoshida is currently concerned is that it seems fewer
researchers conduct high-risk researches. "They have to write papers
continually to get research funds, so they intend to conduct research
with a future. However, it is also very important to work on research
even under uncertainty because it may turn out novel achievement."
says Prof. Yoshida. He expects those courageous researchers will open
new era with their bold ideas.
(Interviewer: Yu Tatsukawa, Cosmopia Inc.)
For more information,
http://www.nanonet.go.jp/english/mailmag/2004/027a.html
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YOUNG RESEARCHERS' INTRODUCTION
Development of nano spectroscopy and its application to
characterization for advanced inorganic materials
(Issued in Japanese: August 26, 2003)
Minoru OSADA, Senior Researcher, Advanced Materials Laboratory,
National Institute for Materials Science
Our group is developing novel characterization techniques for physical
properties in nanoscale structures, which are indispensable tools for
nano science and technology. Recent studies of electronic ceramics
have focused interest in properties of highly integrated devices and
nanoscale structures ("nano-materials"). The use of nanoscale
structures could potentially stabilize and improve properties superior
to those of bulk phase, while the detailed characterization of
properties for these structures is almost always difficult. In
particular, in situ characterization techniques for nanoscale
structures under actual operating conditions (such as temperature,
electric field, etc.) becomes increasingly critical for evaluating
materials' performance but is the most challenging.
We recently established super-high spatial resolution spectroscopy
using an atomic force microscope equipped with near-field optics,
which enables the combined optical characterizations (reflectance,
photoluminescence, Raman spectra) with electronic/magnetic properties
in nanoscale structures. This technique allows one to perform spatial
and temporal characterizations for optical properties and electronic/
magnetic structures at surfaces/interfaces or in nanoscale structures
of various materials. By using this technology, we are now focused on
physical properties in the strongly correlated oxide materials
including superconductivity, colossal magnetoresistance, ferroelectric
property, and searching for their mechanisms and novel giant phenomena
inherent to nanoscale electronic/spin structures.
As a next target, we are also looking at new ways to develop "nano-
analysis" for single-molecule, low-dimensional nano-structures, which
will be a key tool in future nano-technology study.
For more information,
http://www.nanonet.go.jp/english/mailmag/2004/027b.html
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Nanotechnology Researchers Network Center of Japan
Ministry of Education, Culture, Sports, Science and Technology (MEXT)
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