NASA scientists today announced the creation of amino acids, critical for
life, in an environment that mimics deep space. The research will be
published in the March 28 issue of the journal Nature.
In a laboratory at NASA Ames Research Center in California’s Silicon
Valley, the team of astrobiologists shone ultraviolet light on
deep-space-like “ices,” simulating conditions that are commonplace in
interstellar space. Deep-space ice is common water ice laced with simple
molecules. The team subsequently discovered amino acids, molecules present
in, and essential for, life on Earth.
“This finding may shed light on the origin of life itself,” said Dr. Max
Bernstein, the first author and chemist at NASA Ames and the SETI
Institute. “We found that amino acids can be made in the dense
interstellar clouds where planetary systems and stars are made. Our
experiments suggest that amino acids should be everywhere, wherever there
are stars and planets.”
The amino acids they detected (glycine, alanine and serine) are the basic
parts of proteins from which all life is made. Proteins provide the
structure for, and do all the work in, living things.
The amino acids produced in the NASA Ames lab are similar to those found
previously in carbon-rich meteorites. Meteorites are pieces of asteroids or
comets that have fallen to Earth. The chemical similarities may indicate
that amino acids in meteorites were made in deep space, before the solar
system formed, the scientists say.
“This finding suggests that Earth may have been seeded with amino acids
from space in its earliest days,” said Jason Dworkin of Ames and the SETI
Institute. “And, since new stars and planets are formed within the same
clouds in which new amino acids are being created, this increases the odds
that life also evolved in places other than Earth.”
“Taken in combination, these results suggest that interstellar chemistry
may have played a significant part in supplying the Earth with some of the
organic materials needed to jump-start life,” Dworkin concluded.
To conduct their experiments, the research team simulated space-like
conditions by freezing mixtures of molecules (such as wood alcohol and
ammonia) that are abundant in interstellar clouds. They then exposed the
resulting ice to ultraviolet light.
Previously, the team demonstrated that irradiating interstellar ice
‘look-alikes’ generated compounds called amphiphiles that can organize
themselves to form membranes; and molecules called quinones that play
important roles in the metabolism of all living organisms on Earth. The
next step, they say, will be to tackle the issue of left- and right-handed
amino acids. Both forms exist in space, but only the left-handed forms are
used by life on Earth.
In addition to the principals, other scientists on the team included Drs.
Louis Allamandola, George Cooper and Scott Sandford, all of Ames.
Astrobiology is the multidisciplinary study of the origin, evolution,
distribution and future of life in the universe. NASA Ames Research Center
is the location of the central offices of the NASA Astrobiology Institute
and serves as the agency’s lead center for astrobiology.
More detailed information about these findings is available at:
http://web99.arc.nasa.gov/~astrochem/aanature.html
