The Building Blocks of Life on Earth

28/03/2018

Chemists from RWTH Aachen University demonstrate for the first time that the mechanical energy generated in a meteor strike could have generated the first amino acids from simple chemical components.

According to the RWTH researchers, meteoric events could have generated the molecules that made life on Earth possible. Their experiments show that the mechanical energy released during an impact could have transformed simple chemicals into amino acids. The results from these experiments have now been published in the prestigious academic journal 'Angewandte Chemie.'

So far, according to the publication, there are various theories on the transformation of simple chemical components into acids, lipids, carbohydrates and nucleic acids on ancient Earth: volcanic activity in the Hadean or submarine hydrothermal vents may have initiated the required chemical reactions. Now a team around Josť HernŠndez from the Institute of Organic Chemistry, IOC for short, found that a meteoric event could have generated the first amino acids from a few simple components.

Their central finding is that the mechanical forces and friction generated by a meteor strike could have catalyzed chemical reactions – a phenomenon that can be investigated with the help of mechanochemical methods. In mechanochemistry, reactions between chemical ingredients are induced by the input of mechanical energy, typically by grinding in so-called "ball mills," the test tubes of the mechanochemist.

Chemical Reactions on Ancient Earth

The idea that friction between rocks could have triggered reactions on early Earth came to HernŠndez, a research associate in the team of Professor Carsten Bolm, during a holiday in Rome. As he reports in the journal Chemistry World, "I was standing in front of the Coliseum. Everybody was taking pictures but I was looking at the floor and saw these very round stones." He took some of these stones back home and found they could replace the metal milling balls typically used in mechanomechanical experiments.

As he explains in 'Chemistry World,'"There have been many studies that have shown meteorites as shuttles for material that ends up on Earth. But we were interested if the mechanical energy of those landings could have activated certain chemical systems." His team set out to simulate this process and succeeded in generating α-aminonitriles, precursors to amino acids.

HernŠndez and his team were actually surprised that the reaction took place at all, as cyanide was missing as a key ingredient. Although potassium cyanoferrate is a potential source that could have existed on early Earth, it is highly stable and only releases hydrogen cyanide at extreme temperatures. HernŠndez and his team now want to find out if other key prebiotic molecules, such as nucleobases or cyanamide, can be made using a mechanochemical approach.