(ORDO NEWS) — The researchers took a new step towards understanding the origin of life by showing that peptides can form on the surface of dust particles under conditions close to those of outer space.
Therefore, these molecules, which are one of the most important “building blocks” of all life forms, could possibly form in cosmic molecular clouds.
Peptides in a living organism perform various functions – they are involved in the transport of substances, accelerate biochemical reactions and form supporting structures in cells.
Peptides are made up of individual amino acids linked in a specific order. The sequence of amino acids in the peptide chain determines its final properties.
However, the origin of these versatile biological molecules is still a mystery. The amino acids, nitrogenous bases, and various sugars found in meteorites, for example, may be of extraterrestrial origin.
However, the formation of a peptide from molecules of individual amino acids requires special conditions, which, as previously thought, are more likely for the Earth.
“Water plays an important role in the ‘traditional’ mechanism of peptide formation,” said Serge Krasnokutsky of the Institute of Astronomy. Max Planck University of Jena. Friedrich Schiller, Germany. In this process, individual amino acid molecules are joined into chains.
For every two amino acid molecules to combine, one molecule of water needs to be removed. “Our quantum chemical calculations have shown that the amino acid glycine can be formed from its chemical precursor, called aminoketone, by combining the latter with a water molecule.
To put it simply, in this case, the mechanism of water is first attached in the first stage, and in the second stage, the water molecule must be split off.
Realizing that water is ultimately not consumed for the implementation of this two-step mechanism, Krasnokutsky and his team decided to test an alternative mechanism for the formation of peptides from aminoketones that does not include water at all.
To do this, under conditions close to space conditions (on dust particles in a vacuum chamber, at a temperature of about minus 263 degrees Celsius), carbon, ammonia and carbon monoxide were combined with each other.
As a result of these experiments, Krasnokutsky’s team recorded the formation of a polyglycine peptide with a chain length of up to 11 amino acids.
These results confirm the “anhydrous” mechanism of polypeptide formation and indicate that peptides could form in cosmic molecular clouds and therefore be of extraterrestrial origin.
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