Molecular structures of thymidine isomers isolated in low-temperature inert matrices

The Fourier transform infrared spectra of 2`-deoxyribonucleoside — thymidine (dT) in low-temperature Ar matrices are obtained in the range 4000–1300 cm–¹. It is determined that anti-conformers of thymidine are dominant. The ribose rings of the main anti-conformers dT_a0, dT_a1 are in the C2`-endo conformation, but the ribose rings of minor anti-conformers dT_a2, dT_a3 have the C3`-endo conformation, stabilized by intramolecular hydrogen bonds O3`H…O5` and O5`H…O3`, respectively. The main syn-conformer dT_s2 is stabilized by the intramolecular hydrogen bond O5`H…O2 and has C2`-endo conformation of the ribose ring

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

Laboratory astrophysics and astrochemistr

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

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 NH$_3$) 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