Asymmetric photoreactions as the origin of biomolecular homochirality: a critical review.
The role of asymmetric photoreactions (occurring in space or on the primitive Earth) in the origin of biomolecular homochirality is critically reviewed. A general description of the various possible ways for light to interact with chiral molecules is first presented on the basis of a series expansion of the dielectric constant: natural, magnetic and magnetochiral circular dichroism are identified with the first three terms in this development. Natural and magnetochiral circular dichroism may cause, through asymmetric photolysis, an enantiomeric excess in a racemic mixture of chiral molecules irradiated, respectively, by circularly polarized ultraviolet light, or by unpolarized ultraviolet light in the presence of a magnetic field non-perpendicular to the light beam. Terrestrial and extraterrestrial sites matching these conditions are then critically reviewed. Finally, we stress the possibility to arrive at the homochirality of amino acids through a path involving D-ribose during RNA world as an alternative to the usual scenarios operating directly on amino acids.
Jorissen
Alain
A
Institut d'Astronomie et d'Astrophysique, CP 226, and Département de Mathématique, CP 216, Université Libre de Bruxelles, Boulevard du Triomphe, B-1050 Bruxelles, Belgium. ajorisse@astro.ulb.ac.be
Cerf
Corinne
C
D000596:Amino Acids / Q000737:chemistry* / Q000528:radiation effects; D002942:Circular Dichroism; D008968:Molecular Conformation; D010777:Photochemistry; D013237:Stereoisomerism
D000596:Amino Acids