November 19, 2012 - The hunt for the organic molecules that create proteins and enzymes critical for life here on Earth
has largely happened in sophisticated terrestrial laboratories equipped with high-tech gadgetry needed to tease out their presence in space rocks and other extraterrestrial samples. A technologist at NASA's Goddard Space Flight Center
in Greenbelt, Md., now wants to take that search to the sources themselves.
Stephanie Getty, who recently was selected as Goddard's Innovator of the Year for her trailblazing work in the area of advanced instrumentation, has won $1.2 million from NASA's Astrobiology Science and Technology Instrument
Development (ASTID) program to advance the Organics Analyzer for Sampling Icy Surfaces (OASIS). This miniaturized liquid chromatograph-mass spectrometer leverages technologies developed under previous Goddard-sponsored research and development efforts to study the chirality, or "handedness," of amino
acids on the icy moons of the outer planets, asteroids, and Kuiper Belt Objects.
"It's like we're packing up a well-equipped Earth
lab and flying it to an asteroid or another solar system body, where we can get access to a pristine supply of these organic molecules to study," Getty said, adding that by going to the source, scientists reduce the risk of contaminating samples with Earth-borne compounds. "With an instrument like OASIS, we could get that much closer to understanding how organic chemicals formed in the solar system, whether the potential for life exists elsewhere, and what may have seeded life here on Earth."
And OASIS would carry out this science with 100 times greater sensitivity than what was possible with previously flown liquid chromatograph-mass spectrometers, she added.
Why Amino Acids?
The hunt for amino acids in extraterrestrial sources began 50 years ago when scientists discovered a variety of non-terrestrial amino acids in meteorites, remnants of asteroids that had fallen to Earth. Their discovery revolutionized the field of astrobiology, reigniting the question of whether life, as we know it, existed elsewhere in the solar system and beyond.
Amino acids, in part, hold the key to ultimately answering that question. They are the building blocks of proteins—the workhorse molecules of life, used in everything from creating hair and fingernails, to the enzymes that speed up or regulate chemical reactions inside cells. Just as the 26 letters of the alphabet are arranged in limitless combinations to make words, life uses 20 different amino acids in a huge variety of arrangements to build millions of different proteins.
Amino acids demonstrate another interesting characteristic. Although they come in two non-superimposable forms—left-handed and right-handed—only abiotic or non-biological organic compounds use both. The amino acids that give rise to life must have the same orientation or chirality, which means they use only one of the two available mirror images of the amino-acid structure.