Propionamide (C2H5CONH2): The Largest Peptide-Like Molecule In Space

By Keith Cowing
August 11, 2021
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Propionamide (C2H5CONH2): The Largest Peptide-Like Molecule In Space

Peptide bonds, as the molecular bridges that connect amino acids, are crucial to the formation of proteins. Searches and studies of molecules with embedded peptide-like bonds are thus important for the understanding of protein formation in space.

Here we report the first tentative detection of propionamide (C2H5CONH2), the largest peptide-like molecule detected in space toward Sagittarius B2(N1) at a position called N1E that is slightly offset from the continuum peak. A new laboratory measurements of the propionamide spectrum were carried out in the 9-461 GHz, which provide good opportunity to check directly for the transition frequencies of detected interstellar lines of propionamide. Our observing result indicates that propionamide emission comes from the warm, compact cores in Sagittarius B2, in which massive protostellars are forming.

The column density of propionamide toward Sgr B2(N1E) was derived to be 1.5\times 10^{16} cm^-2, which is three fifths of that of acetamide, and one nineteenth of that of formamide. This detection suggests that large peptide-like molecules can form and survive during star-forming process and may form more complex molecules in the interstellar medium. The detection of propionamide bodes well for the presence of polypeptides, as well as other complex prebiotic molecules in the interstellar medium.

Juan Li, Junzhi Wang, Xing Lu, Vadim Ilyushin, Roman A. Motiyenko, Qian Gou, Eugene A. Alekseev, Donghui Quan, Laurent Margules, Feng Gao, Frank J. Lovas, Yajun Wu, Edwin Bergin, Shanghuo Li, Zhiqiang Shen, Fujun Du, Meng Li, Siqi Zheng, Xingwu Zheng

Comments: 49 pages, 13 figures, accepted by ApJ
Subjects: Astrophysics of Galaxies (astro-ph.GA); Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2108.05001 [astro-ph.GA] (or arXiv:2108.05001v1 [astro-ph.GA] for this version)
Submission history
From: Juan Li
[v1] Wed, 11 Aug 2021 02:58:53 UTC (4,234 KB)
Astrobiology, Astrochemistry,

SpaceRef co-founder, Explorers Club Fellow, ex-NASA, Away Teams, Journalist, Space & Astrobiology, Lapsed climber.