Parity-Violating Energy Shifts of Murchison L-Amino Acids are Consistent with an Electroweak Origin of Meteorite L-Enantiomeric Excesses

• Published in: Origins of life and evolution of biospheres Vol. 39; no. 5; pp. 459 - 478
• Main Authors: MacDermott, A. J., Fu, T., Nakatsuka, R., Coleman, A. P., Hyde, G. O.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.10.2009; Springer Nature B.V
• Subjects: Amino acids; Amino Acids - chemistry; Asteroids; Astronomy; Astrophysics and Astroparticles; Biochemistry; Biomedical and Life Sciences; Chirality; Deuterium; Earth Sciences; Hydrogen isotopes; Isoleucine; Life Sciences; Meteorites; Meteors & meteorites; Models, Molecular; Observations and Techniques; Stereoisomerism; Studies; Thermodynamics; Meteorite L-enantiomeric excesses; Murchison L-amino acids; Parity-violating energy shifts
• ISSN: 0169-6149; 1573-0875
• DOI: 10.1007/s11084-009-9162-9

In 1996, four α -methyl amino acids in the Murchison meteorite—L-isovaline, L- α -methylnorvaline, L- α -methyl-allo-isoleucine and L- α -methyl-isoleucine—were found to show significant enantiomeric excesses of the L form, ranging from 2% to 9%. Their deuterium to hydrogen isotope ratios suggest they formed in the pre-solar interstellar gas cloud rather than during a later aqueous processing phase on the asteroid parent body. In this paper we apply the techniques of the preceding two papers to compute the parity-violating energy shifts of these amino acids. We find that, in the gas phase, the PVESs of the neutral L forms of all four Murchison α -methyl amino acids are decisively negative, and there is even some correlation between the magnitudes of the L-excesses and the magnitudes of the PVESs—all of which is at least consistent with an electroweak origin of the Murchison enantiomeric excesses.