Glycine amino acid transformation under impacts by small solar system bodies, simulated via high-pressure torsion method

TL;DR

This study uses high-pressure torsion to simulate impacts by small solar system bodies on glycine, revealing partial decomposition to ethanol and implications for organic molecule formation in space.

Contribution

It introduces high-pressure torsion as a novel method to simulate space impacts on amino acids, providing new insights into their chemical transformations.

Findings

Glycine decomposes to ethanol under simulated impact conditions.

High-pressure torsion effectively mimics impact effects on organic molecules.

Ethanol detection suggests space impacts could contribute to organic molecule diversity.

Abstract

Impacts by small solar system bodies (meteoroids, asteroids, comets and transitional objects) are characterized by a combination of energy dynamics and chemical modification on both terrestrial and small solar system bodies. In this context, the discovery of glycine amino acid in meteorites and comets has led to a hypothesis that impacts by astronomical bodies could contribute to delivery and polymerization of amino acids in the early Earth to generate proteins as essential molecules for life. Besides the possibility of abiotic polymerization of glycine, its decomposition by impacts could generate reactive groups to form other essential organic biomolecules. In this study, the high-pressure torsion (HPT) method, as a new platform for simulation of impacts by small solar system bodies, was applied to glycine. In comparison with high-pressure shock experiments, the HPT method simultaneously introduces high pressure and deformation strain. It was found that glycine was not polymerized in the experimental condition assayed, but partially decomposed to ethanol under pressures of 1 and 6 GPa and shear strains of <120 m/m. The detection of ethanol implies the inherent availability of remaining nitrogen-containing groups, which can incorporate to the formation of other organic molecules at the impact site. In addition, this finding highlights a possibility of the origin of ethanol previously detected in comets.