Peptide Synthesis under the Alkaline Hydrothermal Conditions on Enceladus

Wataru Takahagi, Kaito Seo, Takazo Shibuya, Yoshinori Takano, Kosuke Fujishima, Masafumi Saitoh, Shigeru Shimamura, Yohei Matsui, Masaru Tomita, Ken Takai

研究成果: Article査読

13 被引用数 (Scopus)

抄録

Chemical evolution is an abiotic reaction process in which complex organic molecules arise from a combination of simple inorganic and organic chemical compounds. To assess the possible ongoing chemical evolution in the subsurface ocean of Saturn's icy satellite Enceladus, we explored the water-rock aqueous reactions and the peptide formation capability under a hydrothermal environment similar to that on Enceladus. It has been suggested that the core of Enceladus has not experienced high temperatures from the time of satellite formation to the present. The major components of the core are assumed to be carbonaceous chondrites; thus, simple organic substances, including amino acids, are likely present in the alkaline seawater of Enceladus. In this study, we conducted a laboratory-based simulation experiment to describe the chemical alteration of six prebiotically abundant amino acids over 147 days under high pressure with thermal cycling (30 to 100 °C) to simulate the water-rock interface of the ocean on Enceladus. As a result, we detected 28 out of 36 possible dipeptide species during the entire reaction period. We propose that peptide-bond formation is coupled to rock surface chemisorption of amino acids under alkaline condition, which was further supported by the elemental analysis showing carbon and nitrogen signature on the rock surface only when amino acids are added. The above result suggests that ongoing chemical evolution on Enceladus is likely producing short abiotic peptides on the porous core surface.

本文言語English
ページ(範囲)2559-2568
ページ数10
ジャーナルACS Earth and Space Chemistry
3
11
DOI
出版ステータスPublished - 2019 11月 21

ASJC Scopus subject areas

  • 地球化学および岩石学
  • 大気科学
  • 宇宙惑星科学

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