doi:10.1038/nindia.2014.31 Published online 12 March 2014
Researchers have used computer-based models to identify the chemical processes that produce amino acid serine in the interstellar medium — the space between stars, which contains gas and dust clouds1 . This takes researchers a step closer to understanding how prebiotic molecules such as amino acids form in the interstellar medium.
Observational data suggest that the interstellar medium is rich in methanol, water, carbon dioxide and even amino acids like glycine. These molecules are thought to hitch a ride on meteorites, which, when they collide with planets like Earth, set off reactions that pave the way for the development of rudimentary life forms. It is difficult to simulate the formation and reactions of amino acids and their precursors in the interstellar medium, as such reactions happen at extremely low densities and temperatures.
To gain insights into such amino-acid-forming reactions in space, the researchers performed computer-based quantum-mechanical calculations, which indicate how serine forms in the interstellar medium at extremely low temperatures.
The researchers found that serine forms in five steps involving both radical–radical and radical–neutral reactions. The first step starts with hydrocarbon radicals and carbon monoxide. The second step results in the formation of the dehydrogenated form of acetic acid. In the third step, the product of the second step reacts with amino and methylene groups, and finally it reacts with the hydroxyl group to form serine.
The researchers say that these results demonstrate an immediate prospect of obtaining the many transitions necessary for a definitive detection of interstellar serine.