Houston,
TX (9/17/98)- Studies of archaea enzymes conducted on the Space Shuttle
could help explain how these organisms survive at extreme temperatures
and pressures and could have far-ranging implications for everything from
exobiology to biotechnology.
Thermophiles exist at
extremes of temperature and pressure
The discovery of 'extremeophile' archaea in 1977 upset the dogma
of that all life forms could be classified as either eukaryotes nor
prokaryotes, and launched a debate on the genetic origins of the novel
life forms. The discovery gave new impetus to the search for the origins
of life on earth, and led to the development of now common biotechnology
processes, particularly PCR.
Italian researchers collected samples of one species of Archaea,
Sulfolobus solfataricus from the Solfatara volcanic area near Naples.
This organism produces an enzyme, alcohol dehydrogenase (ADH), that performs
its duties under the extreme heat and acidic conditions of a volcano. It
can survive to 88 deg. C (190 deg. F) - nearly boiling - and corrosive
acid conditions (pH=3.5) approaching the sulfuric acid found in a car battery
(pH=2). Because it can remain stable under these conditions, and because
it produces ethanol, researchers believe it has considerable potential
for biotechnology applications.
Little is known about the molecular structure of the enzyme, so the
Italian research team designed a protocol to study the enzyme in the low-gravity
conditions of the Space Shuttle. Ultimately, they accompanied their precious
cargo into space and purified the ADH enzyme for crystallization aboard
the Space Shuttle.
The crystals grown in space were nearly 35% better in quality than could
be developed on Earth. This allowed them to obtain diffraction data with
a significantly higher resolution, indicating reduced disorder. They are
now working to use this information learn more about these molecules work.
The primary question asked by the researchers concerns which features
of these volcanic organisms' metabolism provide the thermal stability in
their enzymes. Possible spin-offs from answering this question could include
applications in biotechnological medicines, food and drug preservation,
environmental cleanup, pollution prevention, and energy production.
The fact that archaea can live without sunlight or organic carbon as
food, surviving instead on sulfur, hydrogen, and other chemicals is of
great interest to researchers studying the origins of life on Earth, and
the potential for life to exist on other planets. Some of these researchers
believe that archaea may represent the earliest form of life and may also
be the most likely form of life existing on other planets.
|
What's News Index
