d -Amino acids in molecular evolution in space – Absolute asymmetric photolysis and synthesis of amino acids by circularly polarized light

Abstract

Living organisms on the Earth almost exclusively use l-amino acids for the molecular architecture of proteins. The biological occurrence of d-amino acids is rare, although their functions in various organisms are being gradually understood. A possible explanation for the origin of biomolecular homochirality is the delivery of enantioenriched molecules via extraterrestrial bodies, such as asteroids and comets on early Earth. For the asymmetric formation of amino acids and their precursor molecules in interstellar environments, the interaction with circularly polarized photons is considered to have played a potential role in causing chiral asymmetry. In this review, we summarize recent progress in the investigation of chirality transfer from chiral photons to amino acids involving the two major processes of asymmetric photolysis and asymmetric synthesis. We will discuss analytical data on cometary and meteoritic amino acids and their potential impact delivery to the early Earth. The ongoing and future ambitious space missions, Hayabusa2, OSIRIS-REx, ExoMars 2020, and MMX, are scheduled to provide new insights into the chirality of extraterrestrial organic molecules and their potential relation to the terrestrial homochirality. This article is part of a Special Issue entitled: d-Amino acids: biology in the mirror, edited by Dr. Loredano Pollegioni, Dr. Jean-Pierre Mothet and Dr. Molla Gianluca.

Extra‐Terrestrial Gas‐Phase Stereoinversion in Amino Acid Leucine: Thermal and Photochemical Channels

“…The latter in fact is needed if enantiomeric excess has to be preserved in the ISM. The enantiomeric excess has been proposed to arise due to selective destruction of one enantiomer by circularly polarized UV radiation, an important composition of stellar radiation . However, the present work reveals that there are photochemical channels for stereoinversion, which can be initiated by UV radiation.…”

Further characterization of carbonaceous materials in Hayabusa‐returned samples to understand their origin

“…; Sugahara et al. ), as well as in situ molecular analysis by desorption electrospray ionization coupled with high‐resolution mass spectrometry (Naraoka and Hashiguchi ).…”

“…Once carbonaceous materials are contaminated by terrestrial materials, they are difficult to distinguish from each other. In future work, we will establish a state-of-the-art analytical scheme including combustion and/or dissolution methods for the analysis of higher molecular structures, including high-precision, compound-specific measurement of amino acids with the corresponding stereoisomers (Naraoka et al 2012;Hamase et al 2014;Takano et al 2015;Sugahara et al 2018), as well as in situ molecular analysis by desorption electrospray ionization coupled with high-resolution mass spectrometry (Naraoka and Hashiguchi 2018). witness plate (silicon and fluoro rubber), by FE-SEM-EDS, STXM-XANES, and TEM.…”

The Chirality Induction and Modulation of Polymers by Circularly Polarized Light

“…As shown in Figure 1, CPL is one kind of electromagnetic waves with a spiral arrangement of the electric field vector along the propagation direction [35]. Right and left-handed CPL are considered to be plausible candidates to introduce the initial chiral asymmetry into biomolecular building blocks.…”

“…Compared with these methods, circularly polarized light (CPL), proposed to be one of the origins of homochirality in nature, is regarded as an important tool to prepare photo-active chiral materials [34]. As shown in Figure 1, CPL is one kind of electromagnetic waves with a spiral arrangement of the electric field vector along the propagation direction [35]. Right and left-handed CPL are considered to be plausible candidates to introduce the initial chiral asymmetry into biomolecular building blocks.…”