Analysis of the Stability of Natural and Unnatural Amino Acids in Extraterrestrial Conditions

Abstract

In addition to the 20 natural amino acids used in the genetic codes of most biological organisms, there are hundreds more non‐proteinogenic, or “unnatural” amino acids which could be used in the genetic codes of organisms evolving under conditions different than those on Earth. However, in order for a protein based extraterrestrial life‐form to have evolved in the first place, the amino acids within the organism must be relatively stable in the extraterrestrial environmental conditions In this work, the stability of ten unnatural amino acids and five representative natural amino acids has been tested under a variety of extraterrestrial conditions, such as heat, cold, pH variation, and UV radiation. The environmental conditions selected were intended to potentially mimic the conditions on the three most likely locations of life development within our Solar System: the ice caps of Mars, and the subsurface oceans of the moons Europa and Enceladus. After the amino acids were subjected to these conditions while in solution, their stability was quantified using Ultra‐Performance Liquid Chromatography with UV‐Vis and MS detectors. The area of the parent amino acid peak (determined through MS) on the UV‐Vis chromatogram could then be described as a percentage of the area of all non‐solvent peaks, with any non‐solvent, nonparent peaks representing degradation of the original amino acid. Ultimately, trends in stability could indicate favorable traits for amino acids to possess in order to survive on other planets and moons.Support or Funding InformationThis work has been supported by an Indiana Space Grant consortium grant.