An interstellar energetic and non-aqueous pathway to peptide formation

arXiv:2607.26814 · astro-ph.SR, astro-ph.EP, astro-ph.GA, physics.space-ph · Submitted 2026-07-29 · Read on arXiv

Alfred Thomas Hopkinson, Ann Mary Wilson, Joe Pitfield, Alejandra Traspas Muiña, Richárd Rácz, Duncan V. Mifsud, Péter Herczku, Gergő Lakatos, Béla Sulik, Zoltán Juhász, Sándor Biri, Robert W. McCullough, Nigel J. Mason, Carsten Scavenius, Liv Hornekær, Sergio Ioppolo

Center for Interstellar Catalysis, Aarhus University · Center for Interstellar Catalysis, Aarhus University · Center for Interstellar Catalysis, Aarhus University · School of Electronic Engineering and Computer Science, Queen Mary University of London · HUNREN Institute for Nuclear Research · HUNREN Institute for Nuclear Research · HUNREN Institute for Nuclear Research · Doctoral School of Chemistry, University of Debrecen · HUNREN Institute for Nuclear Research · HUNREN Institute for Nuclear Research · HUNREN Institute for Nuclear Research · Department of Physics and Astronomy, School of Mathematics and Physics, Queens University Belfast · Centre for Astrophysics and Planetary Science · Department of Molecular Biology and Genetics Protein Science, Aarhus University · Interdisciplinary Nanoscience Center, Aarhus University · Center for Interstellar Catalysis, Aarhus University

astro-ph.SR, astro-ph.EP, astro-ph.GA, physics.space-ph

Submitted: 2026-07-29

Comments: 22 pages, 6 figures

Journal ref: Hopkinson, A.T., Wilson, A.M., Pitfield, J. et al. An interstellar energetic and non-aqueous pathway to peptide formation. Nat Astron 10, 531 539 (2026)

DOI: 10.1038/s41550-025-02765-7

License: http://creativecommons.org/licenses/by/4.0/

The gist: The origin of the molecular building blocks of life is a central question in science.

Terminology

Abstract

The origin of the molecular building blocks of life is a central question in science. A few alpha-amino acids such as glycine, the simplest proteinogenic amino acid, have been detected in meteorites and comets, indicating an extraterrestrial origin for some prebiotic molecules. However, the formation of peptides, short chains of alpha-amino acids linked by peptide bonds, under astrophysical conditions has remained unresolved. Here we show that the building blocks of proteins can form in interstellar ice analogues exposed to ionising radiation, without the presence of liquid water. Using isotopically labelled glycine irradiated with protons at cryogenic temperatures, we detect the formation of glycylglycine, the simplest dipeptide, along with deuterated and non-deuterated water as by-products. Peptide bond formation is confirmed by infrared spectroscopy and high-resolution mass spectrometry, which also reveal the production of other complex organic species. These findings demonstrate a non-aqueous route to peptide formation under space-like conditions and suggest that such molecules could form in the cold interstellar medium and be incorporated into forming planetary systems. Our results challenge aqueous-centric models of early biochemical evolution and broaden potential settings for the origins of life.

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