Abstract
The detection of the amino acid glycine and its amine precursor methylamine on the comet 67P/Churyumov-Gerasimenko by the Rosetta mission provides strong evidence for a cosmic origin of amino acids on Earth. How and when such molecules form along the process of star formation remains debated. Here we report the laboratory detection of glycine formed in the solid phase through atom and radical–radical addition surface reactions under dark interstellar cloud conditions. Our experiments, supported by astrochemical models, suggest that glycine forms without the need for ‘energetic’ irradiation (such as ultraviolet photons and cosmic rays) in interstellar water-rich ices, where it remains preserved, during a much earlier star-formation stage than previously assumed. We also confirm that solid methylamine is an important side-reaction product. A prestellar formation of glycine on ice grains provides the basis for a complex and ubiquitous prebiotic chemistry in space enriching the chemical content of planet-forming material.
This is a preview of subscription content, access via your institution
Relevant articles
Open Access articles citing this article.
-
A chemical link between methylamine and methylene imine and implications for interstellar glycine formation
Communications Chemistry Open Access 12 May 2022
-
A pathway to peptides in space through the condensation of atomic carbon
Nature Astronomy Open Access 10 February 2022
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 per month
cancel any time
Subscribe to this journal
Receive 12 digital issues and online access to articles
$119.00 per year
only $9.92 per issue
Rent or buy this article
Get just this article for as long as you need it
$39.95
Prices may be subject to local taxes which are calculated during checkout





Data availability
The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.
Code availability
The codes for Models 1 and 2 are proprietary, but the input and output data are available from the corresponding author upon request.
References
Elsila, J. E., Glavin, D. P. & Dworkin, J. P. Cometary glycine detected in samples returned by Stardust. Meteorit. Planet. Sci. 44, 1323–1330 (2009).
Altwegg, K. et al. Prebiotic chemicals—amino acid and phosphorus—in the coma of comet 67P/Churyumov-Gerasimenko. Sci. Adv. 2, e1600285 (2016).
Cronin, J. R. & Pizzarello, S. Enantiomeric excesses in meteoritic amino acids. Science 275, 951–955 (1997).
Botta, O., Glavin, D. P., Kminek, G. & Bada, J. L. Relative amino acid concentrations as a signature for parent body processes of carbonaceous chondrites. Orig. Life Evol. Biosph. 32, 143–163 (2002).
Cobb, A. K. & Pudritz, R. E. Nature’s starships. I. Observed abundances and relative frequencies of amino acids in meteorites. Astrophys. J. 783, 140–151 (2014).
Hadraoui, K. et al. Distributed glycine in comet 67P/Churyumov-Gerasimenko. Astron. Astrophys. 630, A32 (2019).
Hoppe, P., Rubin, M. & Altwegg, K. Presolar isotopic signatures in meteorites and comets: new insights from the Rosetta mission to comet 67P/Churyumov-Gerasimenko. Space Sci. Rev. 214, 106–133 (2018).
Altwegg, K. et al. Organics in comet 67P—a first comparative analysis of mass spectra from ROSINA-DFMS, COSAC and Ptolemy. Mon. Not. R. Astron. Soc. 469, S130–S141 (2017).
Bernstein, M. P., Dworkin, J. P., Sandford, S. A., Cooper, G. W. & Allamandola, L. J. Racemic amino acids from the ultraviolet photolysis of interstellar ice analogues. Nature 416, 401–403 (2002).
Muñoz Caro, G. M. et al. Amino acids from ultraviolet irradiation of interstellar ice analogues. Nature 416, 403–406 (2002).
Woon, D. E. Pathways to glycine and other amino acids in ultraviolet-irradiated astrophysical ices determined via quantum chemical modeling. Astrophys. J. Lett. 571, L177–L180 (2002).
Ciesla, F. J. & Sandford, S. A. Organic synthesis via irradiation and warming of ice grains in the solar nebula. Science 336, 452–454 (2012).
Bossa, J.-B. et al. Methylammonium methylcarbamate thermal formation in interstellar ice analogs: a glycine salt precursor in protostellar environments. Astron. Astrophys. 506, 601–608 (2009).
Garrod, R. T. A three-phase chemical model of hot cores: the formation of glycine. Astrophys. J. 765, 60–88 (2013).
Sato, A. et al. First-principles study of the formation of glycine-producing radicals from common interstellar species. Mol. Astrophys. 10, 11–19 (2018).
Gerakines, P. A. & Hudson, R. L. The radiation stability of glycine in solid CO2—in situ laboratory measurements with applications to Mars. Icarus 252, 466–472 (2015).
Maté, B., Tanarro, I., Escribano, R., Moreno, M. A. & Herrero, V. J. Stability of extraterrestrial glycine under energetic particle radiation estimated from 2 keV electron bombardment experiments. Astrophys. J. 806, 151–160 (2015).
Ceccarelli, C., Loinard, L., Castets, A., Faure, A. & Lefloch, B. Search for glycine in the solar type protostar IRAS 16293-2422. Astron. Astrophys. 362, 1122–1126 (2000).
Jiménez -Serra, I., Testi, L., Caselli, P. & Viti, S. Detectability of glycine in solar-type system precursors. Astrophys. J. Lett. 787, L33–L37 (2014).
Drozdovskaya, M. N., van Dishoeck, E. F., Rubin, M., Jørgensen, J. K. & Altwegg, K. Ingredients for solar-like systems: protostar IRAS 16293-2422 B versus comet 67P/Churyumov-Gerasimenko. Mon. Not. R. Astron. Soc. 490, 50–79 (2019).
Kaifu, N. et al. Detection of interstellar methylamine. Astrophys. J. Lett. 191, L135–L137 (1974).
Bøgelund, E. G., McGuire, B. A., Hogerheijde, M. R., van Dishoeck, E. F. & Ligterink, N. F. W. Methylamine and other simple N-bearing species in the hot cores NGC 6334I MM1-3. Astron. Astrophys. 624, A82 (2019).
Ohishi, M., Suzuki, T., Hirota, T., Saito, M. & Kaifu, N. Detection of a new methylamine (CH3NH2) source: candidate for future glycine surveys. Publ. Astron. Soc. Jpn 71, 86–96 (2019).
Boogert, A. C. A., Gerakines, P. A. & Whittet, D. C. B. Observations of the icy universe. Annu. Rev. Astron. Astrophys. 53, 541–581 (2015).
Krasnokutski, S. A., Jäger, C. & Henning, T. Condensation of atomic carbon: possible routes toward glycine. Astrophys. J. 889, 67–73 (2020).
Chuang, K.-J., Fedoseev, G., Ioppolo, S., van Dishoeck, E. F. & Linnartz, H. H-atom addition and abstraction reactions in mixed CO, H2CO and CH3OH ices—an extended view on complex organic molecule formation. Mon. Not. R. Astron. Soc. 455, 1702–1712 (2016).
Fedoseev, G. et al. Formation of glycerol through hydrogenation of CO ice under prestellar core conditions. Astrophys. J. 842, 52–60 (2017).
Goumans, T. P. M., Uppal, M. A. & Brown, W. A. Formation of CO2 on a carbonaceous surface: a quantum chemical study. Mon. Not. R. Astron. Soc. 384, 1158–1164 (2008).
Ioppolo, S., Cuppen, H. M., Romanzin, C., van Dishoeck, E. F. & Linnartz, H. Laboratory evidence for efficient water formation in interstellar ices. Astrophys. J. 686, 1474–1479 (2008).
Hidaka, H., Watanabe, M., Kouchi, A. & Watanabe, N. FTIR study of ammonia formation via the successive hydrogenation of N atoms trapped in a solid N2 matrix at low temperatures. Phys. Chem. Chem. Phys. 13, 15798–15802 (2011).
Qasim, D. et al. An experimental study of the surface formation of methane in interstellar molecular clouds. Nat. Astron 4, 781–785 (2020).
Theule, P. et al. Hydrogenation of solid hydrogen cyanide HCN and methanimine CH2NH at low temperature. Astron. Astrophys. 534, A64 (2011).
Bossa, J.-B., Borget, F., Duvernay, F., Theulé, P. & Chiavassa, T. How a usual carbamate can become an unusual intermediate: a new chemical pathway to form glycinate in the interstellar medium. J. Phys. Org. Chem. 23, 333–339 (2010).
Ioppolo, S., van Boheemen, Y., Cuppen, H. M., van Dishoeck, E. F. & Linnartz, H. Surface formation of CO2 ice at low temperatures. Mon. Not. R. Astron. Soc. 413, 2281–2287 (2011).
Fuchs, G. W. et al. Hydrogenation reactions in interstellar CO ice analogues: a combined experimental/theoretical approach. Astron. Astrophys. 505, 629–639 (2009).
NIST Chemistry WebBook Standard Reference Database 69 (NIST, accessed 2020); https://doi.org/10.18434/T4D303
Chaabouni, H., Diana, S., Nguyen, T. & Dulieu, F. Thermal desorption of formamide and methylamine from graphite and amorphous water ice surfaces. Astron. Astrophys. 612, A47 (2018).
Maté, B., Rodriguez-Lazcano, Y., Gálvez, Ó., Tanarro, I. & Escribano, R. An infrared study of solid glycine in environments of astrophysical relevance. Phys. Chem. Chem. Phys. 13, 12268–12276 (2011).
Holtom, P. D., Bennett, C. J., Osamura, Y., Mason, N. J. & Kaiser, R. I. A combined experimental and theoretical study on the formation of the amino acid glycine (NH2CH2COOH) and its isomer (CH3NHCOOH) in extraterrestrial ices. Astrophys. J. 626, 940–952 (2005).
Oba, Y., Chigai, T., Osamura, Y., Watanabe, N. & Kouchi, A. Hydrogen isotopic substitution of solid methylamine through atomic surface reactions at low temperatures: a potential contribution to the D/H ratio of methylamine in molecular clouds. Meteorit. Planet. Sci. 49, 117–132 (2014).
Schuhmann, M. et al. CHO-bearing molecules in comet 67P/Churyumov-Gerasimenko. ACS Earth Space Chem. 3, 1854–1861 (2019).
Cuppen, H. M. & Herbst, E. Simulation of the formation and morphology of ice mantles on interstellar grains. Astrophys. J. 668, 294–309 (2007).
Garrod, R. T., Belloche, A., Müller, H. S. P. & Menten, K. M. Exploring molecular complexity with ALMA (EMoCA): simulations of branched carbon-chain chemistry in Sgr B2(N). Astron. Astrophys. 601, A48 (2017).
Vasyunin, A. I., Caselli, P., Dulieu, F. & Jiménez-Serra, I. Formation of complex molecules in prestellar cores: a multilayer approach. Astrophys. J. 842, 33–50 (2017).
Garrod, R. T. & Pauly, T. On the formation of CO2 and other interstellar ices. Astrophys. J. 735, 15–32 (2011).
Jiménez -Serra, I. et al. The spatial distribution of complex organic molecules in the L1544 pre-stellar core. Astrophys. J. Lett. 830, L6–L13 (2016).
Oba, Y., Watanabe, N., Osamura, Y. & Kouchi, A. Chiral glycine formation on cold interstellar grains by quantum tunneling hydrogen–deuterium substitution reactions. Chem. Phys. Lett. 634, 53–59 (2015).
Ioppolo, S., Fedoseev, G., Lamberts, T., Romanzin, C. & Linnartz, H. SURFRESIDE2: an ultrahigh vacuum system for the investigation of surface reaction routes of interstellar interest. Rev. Sci. Instrum. 84, 073112 (2013).
Tschersich, K. G., Fleischhauer, J. P. & Schuler, H. Design and characterization of a thermal hydrogen atom source. J. Appl. Phys. 104, 034908 (2008).
Anton, R., Wiegner, T., Naumann, W., Liebmann, M. & Klein, C. Design and performance of a versatile, cost-effective microwave electron cyclotron resonance source for surface and thin film processing. Rev. Sci. Instrum. 71, 1177–1180 (2000).
Lamberts, T., Fedoseev, G., Kästner, J., Ioppolo, S. & Linnartz, H. Importance of tunneling in H-abstraction reactions by OH radicals: the case of CH4 + OH studied through isotope-substituted analogs. Astron. Astrophys. 599, A132 (2017).
Fedoseev, G., Cuppen, H. M., Ioppolo, S., Lamberts, T. & Linnartz, H. Experimental evidence for glycolaldehyde and ethylene glycol formation by surface hydrogenation of CO molecules under dense molecular cloud conditions. Mon. Not. R. Astron. Soc. 448, 1288–1297 (2015).
Kofman, V., Witlox, M. J. A., Bouwman, J., ten Kate, I. L. & Linnartz, H. A multifunctional setup to record FTIR and UV-vis spectra of organic molecules and their photoproducts in astronomical ices. Rev. Sci. Instrum. 89, 053111 (2018).
Cuppen, H. M., Karssemeijer, L. J. & Lamberts, T. The kinetic Monte Carlo method as a way to solve the master equation for interstellar grain chemistry. Chem. Rev. 113, 8840–8871 (2013).
Simons, M. A. J., Lamberts, T. & Cuppen, H. M. Formation of COMs through CO hydrogenation on interstellar grains. Astron. Astrophys. 634, A52 (2020).
Cuppen, H. M. et al. Grain surface models and data for astrochemistry. Space Sci. Rev. 212, 1–58 (2017).
Penteado, E. M., Walsh, C. & Cuppen, H. M. Sensitivity analysis of grain surface chemistry to binding energies of ice species. Astrophys. J. 844, 71–83 (2017).
Senevirathne, B., Andersson, S., Dulieu, F. & Nyman, G. Hydrogen atom mobility, kinetic isotope effects and tunneling on interstellar ices (Ih and ASW). Mol. Astrophys. 6, 59–69 (2017).
Ásgeirsson, V., Jónsson, H. & Wikfeldt, K. T. Long-time scale simulations of tunneling-assisted diffusion of hydrogen on ice surfaces at low temperature. J. Phys. Chem. C 121, 1648–1657 (2017).
Garrod, R. T. A new modified-rate approach for gas-grain chemical simulations. Astron. Astrophys. 491, 239–251 (2008).
Kalvāns, J. The efficiency of photodissociation for molecules in interstellar ices. Mon. Not. R. Astron. Soc. 478, 2753–2765 (2018).
Jin, M. & Garrod, R. T. Formation of complex organic molecules in cold interstellar environments through nondiffusive grain-surface and ice-mantle chemistry. Astrophys. J. Suppl. 249, 26–55 (2020).
Le Roy, L. et al. Inventory of the volatiles on comet 67P/Churyumov-Gerasimenko from Rosetta/ROSINA. Astron. Astrophys. 583, A1 (2015).
Gibb, E. L., Whittet, D. C. B., Boogert, A. C. A. & Tielens, A. G. G. M. Interstellar ice: the infrared space observatory legacy. Astrophys. J. Suppl. 151, 35–73 (2004).
Linnartz, H., Ioppolo, S. & Fedoseev, G. Atom addition reactions in interstellar ice analogues. Int. Rev. Phys. Chem. 34, 205–237 (2015).
Persson, M. V. Current view of protostellar evolution (ENG). Figshare https://doi.org/10.6084/m9.figshare.654555.v7 (2014).
Acknowledgements
We thank T. Lamberts and I. Jiménez-Serra for stimulating discussions. This research was funded through a VICI grant of the NWO (the Netherlands Organization for Scientific Research) and A-ERC grant number 291141 (CHEMPLAN). Financial support from the Danish National Research Foundation through the Center of Excellence ‘InterCat’ (Grant agreement no. DNRF150) and from NOVA (the Netherlands Research School for Astronomy) and the Royal Netherlands Academy of Arts and Sciences (KNAW) through a professor prize is acknowledged. S.I. acknowledges the Royal Society for financial support through the University Research Fellowship (grant number UF130409), the University Research Fellowship Renewal 2019 (grant number URF\R\191018), the Research Fellows Enhancement Award (grant number RGF\EA\180306) and the Holland Research School for Molecular Chemistry (HRSMC) for a travel grant. G.F. acknowledges financial support from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie actions grant agreement number 664931 and support from an ‘iALMA’ grant (CUP C52I13000140001) approved by MIUR (Ministero dell’Istruzione, dell’Universitá e della Ricerca). A.R.C. and R.T.G. thank the NASA Astrophysics Research and Analysis Research programme for funding through grant number NNX15AG07G. V.K. was funded by the NWO PEPSci (Planetary and ExoPlanetary Science) programme. This work benefited from collaborations within the framework of the FP7 ITN LASSIE consortium (grant number GA238258).
Author information
Authors and Affiliations
Contributions
S.I. initiated and managed the project and wrote the manuscript with assistance from H.L., H.M.C., A.R.C., R.T.G., G.F. and K.-J.C. E.F.v.D. linked the laboratory and modelling results to astronomical observations. S.I., K.-J.C., G.F., D.Q. and V.K. performed laboratory experiments. H.L. was responsible for laboratory management. H.M.C., A.R.C. and R.T.G. developed and ran kinetic Monte Carlo simulations. M.J. and R.T.G. developed and ran the gas–grain kinetics models. All authors contributed to data interpretation and commented on the paper.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Peer review information Nature Astronomy thanks the anonymous reviewers for their contribution to the peer review of this work.
Supplementary information
Supplementary Information
Supplementary Figs. 1–8, Tables 1–5 and text.
Supplementary Data
Reaction network as included in Model 1.
Rights and permissions
About this article
Cite this article
Ioppolo, S., Fedoseev, G., Chuang, KJ. et al. A non-energetic mechanism for glycine formation in the interstellar medium. Nat Astron 5, 197–205 (2021). https://doi.org/10.1038/s41550-020-01249-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41550-020-01249-0
This article is cited by
-
An Ice Age JWST inventory of dense molecular cloud ices
Nature Astronomy (2023)
-
A pathway to peptides in space through the condensation of atomic carbon
Nature Astronomy (2022)
-
A chemical link between methylamine and methylene imine and implications for interstellar glycine formation
Communications Chemistry (2022)