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Paper: Theoretical Studies of Glutamate Enantiomers at Different pH Conditions
Volume: 420, Bioastronomy 2007: Molecules, Microbes and Extraterrestrial Life
Page: 203
Authors: González, J.; Corredor, C. F.; Lareo, L. R.
Abstract: Life, at least as we know it, is invariably linked to homochirality. Here, we present a new approach to understanding the homochirality using glutamic acid as a model. Glutamic acid is the key amino acid in living organisms. It was probably formed abiotically under conditions prevailing in the early Earth’s atmosphere and its two enantiomers have been found in meteorites. The two enantiomers, however, do not exhibit biological activity to the same extent. The D-enantiomer usually has either very little or no activity as compared to the L enantiomer. In order to find an explanation for the differences, we have undertaken theoretical studies with classical and semi-empirical force field models on solvated L- and D-glutamate. Our results show strong interactions between charged atoms of the D-enantiomer that determine a very rigid spatial configuration resulting in a low capacity to adapt to different environmental conditions and to respond to energy perturbations. Our results might provide a possible explanation for the natural selection of the L-glutamate enantiomer as a basic constituent of living matter.
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