Scientists are looking more closely at the building blocks of life as we know it to try to identify which ingredients might also be the foundation for alien life beyond Earth.
Researchers from Valparaiso University in Indiana have analyzed an assortment of amino acids, which are basic compounds that make the proteins to support life, to see how they might hold up to the harsh conditions on other worlds like Mars or Saturn's moon Enceladus. Their work represents a whole new approach to looking for alien life.
"Our main goal with this research is to see if there are structural characteristics of some amino acids that lead to a higher stability in extraterrestrial conditions and then to see what those characteristics might be," said Claire Mammoser, an undergraduate research assistant in the laboratory of Valparaiso chemistry professor Laura Rowe.
Mammoser is presenting the research Sunday during the American Society for Biochemistry and Molecular Biology's Experimental Biology 2017 meeting in Chicago. She explains that while we know of the 20 natural amino acids such as lysine and tryptophan found in most biological organisms, there are also hundreds of known "unnatural" amino acids on Earth that aren't used by life forms we're familiar with.
"In a different extraterrestrial locale, the proteins in an organism would not necessarily be the same as that of an organism on Earth, so they might use amino acids that are known to us but not used to make proteins on Earth," she said.
To see which amino acids might be most likely to make protein snacks for alien cells, the team ran a selection of both the natural and unnatural compounds through a terrestrial torture test. They subjected vials of the building blocks to extreme temperatures, pH levels, radiation and other conditions that hypothetical Martian microbes and outer solar system swimmers in the hidden oceans of Europa and Enceladus might have to contend with.
The scientists then watched to see which amino acids remain stable, looking for and observing patterns among the toughest types, such as larger size or the ability to bind with water.
"Finding trends in amino acid stability would give us an idea of what sort of amino acids may have survived in outer space long enough to create life," Mammoser explained.
The research team is also beginning a new round of experiments using amino acids extracted from meteorites to get a handle on key characteristics that could lead to some real-life ETs.
The work also raises a bizarre question in today's age of genetic engineering: If we figure out what aliens are made of on Earth before we ever find them elsewhere in the universe, will they still be totally alien when we finally do find some?
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