Hunting the building blocks of alien life

Amino acids extracted from meteorites will soon be tested to see if they are capable of playing a role in extraterrestrial life.

Amino acids – organic compounds based on amine and carboxyl molecules – are the fundamental building blocks of proteins that, in turn, are the basis of all life on Earth. Astrobiologists have long assumed that the most likely types of extraterrestrial life would also arise from a similar amino-acid-protein system.

An extraterrestrial system, however, would not necessarily use the same amino acids – alone or in combination – as those used on this planet.

“They might use amino acids that are known to us but not used to make proteins on Earth,” says Claire Mammoser of Valparaiso University.

With this in mind, Mammoser has recently finished testing 15 amino acids – some used in earthly biology and others not – to see how they might stand up to the rigours of other planetary environments. 

With conditions on Mars, Saturn’s moon Enceladus and Jupiter’s moon Europa in mind, Mammoser and colleagues subjected the amino acids to extreme variations in temperature, pH, ultraviolet and gamma radiation. They recorded the resilience, or lack of it, in each sample, as well as its ability to perform key functions, such as bind to liquid water.

“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,” says Mammoser.

The results of the experiments were presented this week at the American Society for Biochemistry and Molecular Biology annual meeting in Chicago.

The next phase of the research involves conducting the same battery of tests on genuine extraterrestrial amino acids extracted from meteorites. The team will also experiment with novel amino acids created in a number of “origin of life” experiments, some dating back to the 1950s.