Glycine can predate celestial formation

Science and Technology Daily Beijing, November 18 (Intern reporter Zhang Jiaxin) Glycine is the simplest structure of amino acids, but also an important part of life. An international team of astrophysicists and astrophysic modelers at the Astrophysical Laboratory at Leiden Observatory in the Netherlands has shown that glycine can predate the formation of planets and stars. The results were published on the 16th in the journal Nature Astronomy.

The study found that the glycine produced this time formed under harsh conditions simulating space chemistry in the laboratory, meaning it was likely to form in dense interstellar clouds before they were transformed into new stars and planets. In the absence of energy, glycine may form on the surface of icy dust particles through "dark chemistry". The new discoveries provide strong evidence for the cosmic origin of amino acids on Earth.

The lead author of the paper, Dr Sergio Yobolo of Queen Mary University of London, said: "Dark chemistry refers to chemistry that does not require high-energy radiation. In the lab, we were able to simulate conditions in dark interstellar clouds, where cold dust particles are covered with thin layers of ice and subsequently processed by impacting atoms, causing precursor material to fragment and active intermediates to recombine. ”

Comets are the most primitive material in the solar system, and studying comets helps to understand the original chemical composition and state of the solar system. The comet at Comet 67P/Chulyumov-Gracimenko and glycine detected in samples returned to Earth from the Stardust mission suggest that glycine existed long before star formation. Until recently, however, it was thought that the formation of glycine required energy, which set a clear limit on the environment in which glycine was formed. Previous studies have shown that ultraviolet radiation is required to produce this amino acid.

Scientists first proved that the glycine precursor substance detected in the coma of Comet 67P, methanamine, can be formed, which can be counted as the "raw material" of glycine. The scientists then used ultra-high vacuum devices, a series of atomic beams and diagnostic tools to confirm that glycine can also be formed and that the presence of water ice is essential in the process.

Professor Herma Kuben of the University of Nijmegen in the Netherlands, who is responsible for some of the modelling studies in the paper, said: "From this we have found that over time, small but considerable amounts of glycine can form in space. ”

"In the evolution of star-forming regions, glycine formed so early, which means that this amino acid can form anywhere in space and remain in the ice before comets and starbeams appear." Dr. Jopolot concluded, "Once formed, glycine can also become a precursor to other complex organic molecules. "By the same mechanism, other functional groups (atoms or groups of atoms that determine the chemical properties of organic compounds) can be added to the glycine backbone, forming other amino acids in the interstellar dark cloud, such as alanine and serine. Eventually, this abundance of organic molecules could be found in celestial bodies such as comets, or it could be "teleported" to our Planet and many other planets.

Source: Science and Technology Daily