On the Origins of Life's Homochirality: Inducing Enantiomeric Excess with Spin-Polarized Electrons

Fuente: arXiv
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Autores principales: Ozturk, S. Furkan, Sasselov, Dimitar D.
Formato: Preprint
Publicado: 2022
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author Ozturk, S. Furkan
Sasselov, Dimitar D.
author_facet Ozturk, S. Furkan
Sasselov, Dimitar D.
contents Life as we know it is homochiral, but the origins of biological homochirality on early Earth remain elusive. Shallow closed-basin lakes are a plausible prebiotic environment on early Earth, and most are expected to have significant sedimentary magnetite deposits. We hypothesize that UV (200-300nm) irradiation of magnetite deposits could generate hydrated spin-polarized electrons sufficient to induce chirally selective prebiotic chemistry. Such electrons are potent reducing agents that drive reduction reactions where the spin polarization direction can alter enantioselectively the reaction kinetics. Our estimate of this chiral bias is based on the strong effective spin-orbit coupling observed in the chiral-induced spin selectivity (CISS) effect, as applied to energy differences in reduction reactions for different isomers. In the original CISS experiments, spin selective electron transmission through a monolayer of dsDNA molecules is observed at room temperature - indicating a strong coupling between molecular chirality and electron spin. We propose that the chiral symmetry breaking due to the CISS effect, when applied to reduction chemistry, can induce enantioselective synthesis on the prebiotic Earth and thus facilitate the homochiral assembly of life's building blocks.
format Preprint
id arxiv_https___arxiv_org_abs_2203_16011
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle On the Origins of Life's Homochirality: Inducing Enantiomeric Excess with Spin-Polarized Electrons
Ozturk, S. Furkan
Sasselov, Dimitar D.
Chemical Physics
Biological Physics
Life as we know it is homochiral, but the origins of biological homochirality on early Earth remain elusive. Shallow closed-basin lakes are a plausible prebiotic environment on early Earth, and most are expected to have significant sedimentary magnetite deposits. We hypothesize that UV (200-300nm) irradiation of magnetite deposits could generate hydrated spin-polarized electrons sufficient to induce chirally selective prebiotic chemistry. Such electrons are potent reducing agents that drive reduction reactions where the spin polarization direction can alter enantioselectively the reaction kinetics. Our estimate of this chiral bias is based on the strong effective spin-orbit coupling observed in the chiral-induced spin selectivity (CISS) effect, as applied to energy differences in reduction reactions for different isomers. In the original CISS experiments, spin selective electron transmission through a monolayer of dsDNA molecules is observed at room temperature - indicating a strong coupling between molecular chirality and electron spin. We propose that the chiral symmetry breaking due to the CISS effect, when applied to reduction chemistry, can induce enantioselective synthesis on the prebiotic Earth and thus facilitate the homochiral assembly of life's building blocks.
title On the Origins of Life's Homochirality: Inducing Enantiomeric Excess with Spin-Polarized Electrons
topic Chemical Physics
Biological Physics
url https://arxiv.org/abs/2203.16011