A pathway to peptides in space through the condensation of atomic carbon

S A Krasnokutski,C Jäger,K.-J Chuang,N Ueberschaar,Th Henning

doi:10.1038/s41550-021-01577-9

Abstract

Organic molecules are widely present in the dense interstellar medium, and many have been synthesized in the laboratory on Earth under the conditions typical for an interstellar environment. Until now, however, only relatively small molecules of biological interest have been demonstrated to form experimentally under typical space conditions. Here we prove experimentally that the condensation of carbon atoms on the surface of cold solid particles (cosmic dust) leads to the formation of isomeric polyglycine monomers (aminoketene molecules). Following encounters between aminoketene molecules, they polymerize to produce peptides of different lengths. The chemistry involves three of the most abundant species (CO, C and NH3) present in star-forming molecular clouds, and proceeds via a novel pathway that skips the stage of amino acid formation in protein synthesis. The process is efficient, even at low temperatures, without irradiation or the presence of water. The delivery of biopolymers formed by this chemistry to rocky planets in the habitable zone might be an important element in the origins of life.

Highlights

Organic molecules are widely present in the dense interstellar medium, and many have been synthesized in the laboratory on Earth under the conditions typical for an interstellar environment
Analysis of meteoritic material led to the identification of amino acids, sugars and nucleobases, among other complex organic molecules of extraterrestrial origin[3,4]
The widespread hypothesis of the formation of organic molecules in space suggests that they are synthesized in the icy mantle that covers the refractory particles of cosmic dust[6,7]

Summary

Introduction

Organic molecules are widely present in the dense interstellar medium, and many have been synthesized in the laboratory on Earth under the conditions typical for an interstellar environment. The formation of various amino acids, and even their dimers (as well as other organic molecules) has been detected following energetic processing of different molecular ices[11,12].

Results

Conclusion