Abstract
Hydrophobic polymer amide (HPA) could have been one of the first normal density materials to accrete in space. We present ab initio calculations of the energetics of amino acid polymerization via gas phase collisions. The initial hydrogen-bonded di-peptide is sufficiently stable to proceed in many cases via a transition state into a di-peptide with an associated bound water molecule of condensation. The energetics of polymerization are only favorable when the water remains bound. Further polymerization leads to a hydrophobic surface that is phase-separated from, but hydrogen bonded to, a small bulk water complex. The kinetics of the collision and subsequent polymerization are discussed for the low-density conditions of a molecular cloud. This polymer in the gas phase has the properties to make a topology, viz. hydrophobicity allowing phase separation from bulk water, capability to withstand large temperature ranges, versatility of form and charge separation. Its flexible tetrahedral carbon atoms that alternate with more rigid amide groups allow it to deform and reform in hazardous conditions and its density of hydrogen bonds provides adhesion that would support accretion to it of silicon and metal elements to form a stellar dust material.
Highlights
Hydrophobic polymer amide (HPA) analyzed by electron microscopy and electron diffraction, has been shown to form an encapsulating skin over water [1]
We discuss below the astrophysical data that shows 12.7 Gy before the present (12.7 Gya) to be the earliest time for H, C, N and O to co-exist in a density and temperature range suitable for gas phase reactions to lead to amino acids, the latter being the basic units of HPA
We examine the gas phase reactions of amino acids, taking terrestrial types as a first case in point, in order to find whether gas phase polymerization is likely, and to determine the fate of the water released in the amino acid polymerization reaction
Summary
Hydrophobic polymer amide (HPA) analyzed by electron microscopy and electron diffraction, has been shown to form an encapsulating skin over water [1]. In this paper we consider the possibility that this material, which is represented in living organisms by a protein that has remained essentially unchanged in its DNA code sequence for 3.8 Gy on Earth, could have formed as a type much earlier in the universe when its constituent elements first came into existence. We examine the gas phase reactions of amino acids, taking terrestrial types as a first case in point, in order to find whether gas phase polymerization is likely, and to determine the fate of the water released in the amino acid polymerization (condensation) reaction. We find that water of condensation tends to collect on one side of the polymer starting the bulking process of water
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