High-Pressure Torsion-Induced Transformation of Adenosine Monophosphate: Insights into Prebiotic Chemistry of RNA by Astronomical Impacts

The origin of life is yet a compelling scientific mystery that has sometimes been attributed to high-pressure impacts by small solar system bodies such as comets, meteoroids, asteroids, and transitional objects. High-pressure torsion (HPT) is an innovative method with which to simulate the extreme conditions of astronomical impacts and offers insights relevant to prebiotic chemistry. In the present study, we investigated the polymerization and stability of adenosine monophosphate (AMP), a key precursor to ribonucleic acid (RNA), in dry and hydrated conditions (10 wt% water) under 6 GPa at ambient and boiling water temperatures. Comprehensive analyses with the use of X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, nuclear magnetic resonance, scanning electron microscopy, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry revealed no evidence of polymerization, while AMP partly transformed to other organic compounds such as nucleobase-derived fragments of adenine, phosphoribose fragments, dehydrated adenosine, protonated adenosine, and oxidized adenosine. The torque measurements during HPT further highlight the mechanical behavior of AMP under extreme conditions. These findings suggest that, while HPT under the conditions tested does not facilitate polymerization, the formation of various compounds from AMP confirms the significance of astronomical impacts on the prebiotic chemistry of RNA on early Earth. Keywords: Ribonucleic acid (RNA), Origin of life; Phase transformations; Chemical reactions, Small solar system bodies

💡 Research Summary

The authors set out to test whether the extreme physical conditions generated by astronomical impacts could drive the polymerization of a key RNA precursor, adenosine‑5′‑monophosphate (AMP). To mimic impact‑related pressure, temperature, and shear, they employed high‑pressure torsion (HPT), a technique that simultaneously applies a static pressure of 6 GPa, a large shear strain (γ≈120) generated by three rotations of the lower anvil at 1 rpm, and controlled temperatures of either 300 K (ambient) or 373 K (boiling water). AMP was examined in two moisture regimes: a dry powder and a hydrated powder containing 10 wt % water, reflecting the likely diversity of early‑Earth environments.

Sample discs (5 mm radius, 0.8 mm thick) were first compacted at 300 MPa, then subjected to HPT. The authors monitored torque in situ to obtain shear‑stress versus shear‑strain curves, comparing the mechanical response of AMP with that of aluminum and copper.

A comprehensive suite of analytical techniques was applied before and after HPT: X‑ray diffraction (XRD) to assess crystallinity, Raman spectroscopy for vibrational fingerprints, FTIR for functional‑group changes, 1H, 13C, and 31P nuclear magnetic resonance (NMR) for molecular‑level structural information, scanning electron microscopy (SEM) for morphology, and matrix‑assisted laser desorption/ionization time‑of‑flight mass spectrometry (MALDI‑TOF) to detect any oligomers or fragments.

The XRD patterns showed that the bulk crystalline lattice of AMP largely survived the treatment, but a broad hump between 15° and 30° 2θ indicated significant amorphization, especially after the 373 K runs. Peak shifts to lower angles suggested lattice expansion, likely due to point‑defect formation. Raman spectra retained the characteristic AMP bands but displayed increased background and loss of some peaks, consistent with defect generation and partial structural breakdown. FTIR revealed no new absorption bands; the original phosphate, ribose, and adenine vibrations were only slightly shifted, indicating that new covalent bonds (e.g., phosphodiester linkages) did not form.

NMR spectra confirmed the presence of AMP’s signature resonances but also showed altered line shapes, intensity changes, and minor chemical‑shift variations. Importantly, 31P NMR did not reveal signals for ADP or ATP, ruling out the formation of higher‑order phosphates.

MALDI‑TOF analysis was the most decisive: the AMP molecular ion (m/z = 347.5) decreased after HPT at 300 K and vanished completely after the 373 K treatment. New peaks appeared at m/z = 135.1 (adenine, C5H5N5), 189.3 and 211.3 (phosphoribose fragments, C5H9O5P), 249.5 (dehydrated adenosine, C10H11N5O3), 267.5 (protonated adenosine, C10H14N5O4⁺), and 283.2 (oxidized adenosine, C10H13N5O5). These fragments were corroborated by NMR, which showed signals attributable to free adenine and adenosine, confirming that AMP primarily decomposes rather than polymerizes under the tested conditions.

SEM images demonstrated that samples processed at 300 K became more irregular, whereas those treated at 373 K showed pronounced particle consolidation, a typical outcome of severe plastic deformation under high pressure. The shear‑stress versus strain curves indicated strain hardening of AMP, with hydrated samples exhibiting slightly lower stresses. At 373 K the steady‑state shear strength of AMP was higher than that of aluminum but slightly below copper, illustrating that an organic solid can develop substantial mechanical resistance under HPT.

Overall, the study provides clear experimental evidence that HPT—designed to emulate the combined pressure, temperature, and shear of asteroid or comet impacts—does not promote the formation of RNA‑like polymers from AMP. Instead, the nucleotide undergoes fragmentation into nucleobase, phosphoribose, and modified adenosine species. This suggests that early‑Earth impact events may have contributed to chemical diversity by breaking down existing nucleotides and generating a pool of smaller organic molecules, rather than directly synthesizing long RNA chains. The work also validates HPT as a versatile laboratory analogue for impact‑driven chemistry, offering a controllable platform to explore other prebiotic pathways under realistic mechanical stress.